diff --git a/README.md b/README.md
deleted file mode 100644
index c8e97a6..0000000
--- a/README.md
+++ /dev/null
@@ -1,2 +0,0 @@
-# mathpaper
-
diff --git a/doc/README.md b/doc/README.md
new file mode 100644
index 0000000..34124b9
--- /dev/null
+++ b/doc/README.md
@@ -0,0 +1,148 @@
+# 数学试卷生成系统
+
+## 项目简介
+
+这是一个智能数学试卷生成系统，能够根据不同年级（小学、初中、高中）自动生成相应难度的数学题目，并保存为试卷文件。
+
+## 系统特性
+
+### 🎯 核心功能
+- **多年级支持**：支持小学、初中、高中三个年级的题目生成
+- **智能题目生成**：根据年级自动调整题目难度和类型
+- **重复检测**：防止生成重复题目，确保试卷质量
+- **文件保存**：自动保存试卷到指定目录，支持时间戳命名
+
+### 🚀 性能优化
+- **高效缓存机制**：智能缓存用户题目，支持LRU和时间过期策略
+- **优化文件I/O**：使用NIO和缓冲区提升文件操作性能
+- **内存管理**：自动清理过期缓存，防止内存泄漏
+- **异常处理**：完善的错误处理和降级机制
+
+### 🎨 用户体验
+- **美观界面**：现代化的控制台界面设计
+- **进度显示**：题目生成过程中显示实时进度条
+- **即时预览**：生成完成后立即预览题目内容
+- **友好提示**：清晰的操作指引和状态反馈
+
+## 题目类型
+
+### 小学数学
+- 基础四则运算（加减乘除）
+- 简单括号表达式
+- 数值范围：1-100
+
+### 初中数学
+- 复杂四则运算
+- 多层括号嵌套
+- 平方运算
+- 数值范围：1-1000
+
+### 高中数学
+- 三角函数（sin, cos, tan）
+- 根式运算（√）
+- 幂运算（x²）
+- 复合函数表达式
+- 数值范围：1-10000
+
+## 系统架构
+
+```
+src/com/mathpaper/
+├── Main.java                 # 主程序入口
+├── model/
+│   └── User.java            # 用户模型
+├── generator/
+│   ├── QuestionGenerator.java    # 题目生成器接口
+│   ├── PrimaryGenerator.java     # 小学题目生成器
+│   ├── JuniorGenerator.java      # 初中题目生成器
+│   └── SeniorGenerator.java      # 高中题目生成器
+└── util/
+    ├── FileUtil.java        # 文件操作工具
+    └── DuplicateChecker.java # 重复检测工具
+```
+
+## 使用方法
+
+### 启动程序
+```bash
+# Windows PowerShell
+.\start.ps1
+
+# 或直接运行
+java com.mathpaper.Main
+```
+
+### 操作流程
+1. **登录**：输入用户名（3-20位字母、数字或下划线）
+2. **选择年级**：选择小学、初中或高中
+3. **生成试卷**：输入题目数量（1-50道）
+4. **查看结果**：系统自动保存并预览生成的试卷
+
+### 文件结构
+```
+doc/paper/用户名/时间戳.txt
+```
+例如：`doc/paper/test123/2025-09-28-22-50-30.txt`
+
+## 技术特点
+
+### 代码质量
+- **模块化设计**：清晰的分层架构，职责分离
+- **设计模式**：使用工厂模式、策略模式等
+- **异常处理**：完善的错误处理和用户友好的提示
+- **代码规范**：统一的编码风格和命名规范
+
+### 性能优化
+- **缓存策略**：
+  - LRU缓存淘汰算法
+  - 时间过期自动清理
+  - 最大缓存用户数限制
+- **文件I/O优化**：
+  - NIO文件操作
+  - 8KB缓冲区
+  - UTF-8编码支持
+- **内存管理**：
+  - 自动垃圾回收
+  - 资源及时释放
+  - 内存泄漏防护
+
+### 用户体验
+- **响应式界面**：实时进度反馈
+- **智能提示**：操作指引和错误提示
+- **数据验证**：输入参数严格验证
+- **容错处理**：优雅的错误恢复机制
+
+## 开发环境
+
+- **Java版本**：Java 8+
+- **编码格式**：UTF-8
+- **操作系统**：Windows/Linux/macOS
+- **依赖**：无外部依赖，纯Java实现
+
+## 版本历史
+
+### v2.1 (当前版本)
+- ✅ 完成性能优化和代码重构
+- ✅ 优化用户界面和交互体验
+- ✅ 增强缓存机制和内存管理
+- ✅ 改进文件I/O操作效率
+- ✅ 完善异常处理和错误恢复
+
+### v2.0
+- ✅ 重构代码架构，提升可维护性
+- ✅ 优化题目生成算法
+- ✅ 增加重复检测功能
+- ✅ 改进用户界面设计
+
+### v1.0
+- ✅ 基础功能实现
+- ✅ 多年级题目生成
+- ✅ 文件保存功能
+
+## 贡献指南
+
+欢迎提交Issue和Pull Request来改进这个项目！
+
+## 许可证
+
+本项目采用MIT许可证。
\ No newline at end of file
diff --git a/doc/bin/start.bat b/doc/bin/start.bat
new file mode 100644
index 0000000..e86b85c
--- /dev/null
+++ b/doc/bin/start.bat
@@ -0,0 +1,15 @@
+@echo off
+chcp 65001 >nul
+echo 启动数学试卷生成系统...
+echo.
+echo === 可用用户账号 ===
+echo 小学用户: 张三1, 张三2, 张三3, zhangsan1, zhangsan2, zhangsan3
+echo 初中用户: 李四1, 李四2, 李四3, lisi1, lisi2, lisi3  
+echo 高中用户: 王五1, 王五2, 王五3, wangwu1, wangwu2, wangwu3
+echo 测试账号: test123, 测试
+echo ===============================
+echo.
+echo 正在启动程序...
+cd /d "%~dp0..\.."
+java -cp src com.mathpaper.Main
+pause
\ No newline at end of file
diff --git a/doc/bin/start.ps1 b/doc/bin/start.ps1
new file mode 100644
index 0000000..bab752a
--- /dev/null
+++ b/doc/bin/start.ps1
@@ -0,0 +1,28 @@
+# Math Paper Generation System Startup Script
+# Automatically set UTF-8 encoding and start the program
+
+Write-Host "启动数学试卷生成系统..." -ForegroundColor Green
+
+# Set console encoding to UTF-8
+Write-Host "设置字符编码为UTF-8..." -ForegroundColor Yellow
+[Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+[Console]::InputEncoding = [System.Text.Encoding]::UTF8
+
+Write-Host "编码设置完成！" -ForegroundColor Green
+Write-Host ""
+
+# Display available user accounts
+Write-Host "=== 可用用户账号 ===" -ForegroundColor Cyan
+Write-Host "小学用户: 张三1, 张三2, 张三3, zhangsan1, zhangsan2, zhangsan3" -ForegroundColor White
+Write-Host "初中用户: 李四1, 李四2, 李四3, lisi1, lisi2, lisi3" -ForegroundColor White  
+Write-Host "高中用户: 王五1, 王五2, 王五3, wangwu1, wangwu2, wangwu3" -ForegroundColor White
+Write-Host "测试账号: test123, 测试" -ForegroundColor White
+Write-Host "===============================" -ForegroundColor Cyan
+Write-Host ""
+
+# Change to project root directory
+Set-Location (Join-Path $PSScriptRoot "..\..")
+
+# Start Java program
+Write-Host "正在启动程序..." -ForegroundColor Green
+java -cp src com.mathpaper.Main
\ No newline at end of file
diff --git a/doc/paper/abc/2025-09-28-23-33-37.txt b/doc/paper/abc/2025-09-28-23-33-37.txt
new file mode 100644
index 0000000..b875614
--- /dev/null
+++ b/doc/paper/abc/2025-09-28-23-33-37.txt
@@ -0,0 +1,5 @@
+1. 82 + 16 + 23 * (35 + 94)
+
+2. 56
+
+3. 23 + 90 - 15 * (76 + 26)
\ No newline at end of file
diff --git a/doc/paper/admin/2025-09-28-23-33-35.txt b/doc/paper/admin/2025-09-28-23-33-35.txt
new file mode 100644
index 0000000..b427967
--- /dev/null
+++ b/doc/paper/admin/2025-09-28-23-33-35.txt
@@ -0,0 +1,5 @@
+1. 42 - 60
+
+2. (19 * 60 + 9) + 64 + 89
+
+3. 79
\ No newline at end of file
diff --git a/doc/paper/admin/2025-09-28-23-33-37.txt b/doc/paper/admin/2025-09-28-23-33-37.txt
new file mode 100644
index 0000000..f4ae68d
--- /dev/null
+++ b/doc/paper/admin/2025-09-28-23-33-37.txt
@@ -0,0 +1,5 @@
+1. 69 + 54 * 22
+
+2. 6
+
+3. 32 / 24 / 47
\ No newline at end of file
diff --git a/doc/paper/admin123/2025-09-28-23-33-36.txt b/doc/paper/admin123/2025-09-28-23-33-36.txt
new file mode 100644
index 0000000..d7682ed
--- /dev/null
+++ b/doc/paper/admin123/2025-09-28-23-33-36.txt
@@ -0,0 +1,5 @@
+1. 31 / (37 / 66)
+
+2. 61 / 34 + (91 * 94) + 78
+
+3. 93 + 77 * 2 + 54
\ No newline at end of file
diff --git a/doc/paper/admin123/2025-09-28-23-33-37.txt b/doc/paper/admin123/2025-09-28-23-33-37.txt
new file mode 100644
index 0000000..eb0bed2
--- /dev/null
+++ b/doc/paper/admin123/2025-09-28-23-33-37.txt
@@ -0,0 +1,5 @@
+1. 47 * 35
+
+2. (25 + 39 / 16) * 2 - 93
+
+3. 28 + 60
\ No newline at end of file
diff --git a/doc/paper/null/2025-09-28-23-33-36.txt b/doc/paper/null/2025-09-28-23-33-36.txt
new file mode 100644
index 0000000..843d11f
--- /dev/null
+++ b/doc/paper/null/2025-09-28-23-33-36.txt
@@ -0,0 +1,5 @@
+1. 20 * 32
+
+2. 74 + 35
+
+3. 95 * 14
\ No newline at end of file
diff --git a/doc/paper/primary1/2025-09-28-21-58-30.txt b/doc/paper/primary1/2025-09-28-21-58-30.txt
new file mode 100644
index 0000000..379d618
--- /dev/null
+++ b/doc/paper/primary1/2025-09-28-21-58-30.txt
@@ -0,0 +1,23 @@
+1. 100 - 55 + 32
+
+2. 80
+
+3. 92
+
+4. 76 * 100 / 2 / 73 * 6
+
+5. 37 * 52 + 90
+
+6. 36 - 73
+
+7. 26 * (95 * 90) + 60
+
+8. 100
+
+9. 82 - 2
+
+10. 67
+
+11. 27 * 22 / 30 * 52
+
+12. 98 - 41 / (95 / 83)
\ No newline at end of file
diff --git a/doc/paper/test123/2025-09-28-22-48-11.txt b/doc/paper/test123/2025-09-28-22-48-11.txt
new file mode 100644
index 0000000..e3a3038
--- /dev/null
+++ b/doc/paper/test123/2025-09-28-22-48-11.txt
@@ -0,0 +1,9 @@
+1. 77
+
+2. 10 - (98 * 46)
+
+3. (63 + 61 * 45)
+
+4. 10 + 98
+
+5. (51 - 48 + 2)
\ No newline at end of file
diff --git a/doc/paper/test123/2025-09-28-22-50-30.txt b/doc/paper/test123/2025-09-28-22-50-30.txt
new file mode 100644
index 0000000..c860a04
--- /dev/null
+++ b/doc/paper/test123/2025-09-28-22-50-30.txt
@@ -0,0 +1,39 @@
+1. sin(3) * tan(3)
+
+2. tan(√(5+2)) + tan(5) - 8 / 10 + 4
+
+3. sin(6) / sin(2) + 6 * 4^2 + √7
+
+4. tan(7) - 7^2 - (3 * 1 * tan(3))
+
+5. cos(5) - √2 / 4^2
+
+6. tan(√(8+4)) - 1
+
+7. sin(√(8+2)) + √7 * 8
+
+8. tan(√(4+4)) - tan(9) + √3 + √3
+
+9. cos(3) - 5
+
+10. sin(2) / tan(2) / 7
+
+11. cos(3) * 4 * 5
+
+12. sin(6) / sin(4) - 6^2 + 7
+
+13. tan(√(8+3)) - tan(9) / 10 / 7
+
+14. cos(6) - √9 - 9^2 + 2^2 * 2^2
+
+15. tan(10) - 7 (* tan(6) + 9)
+
+16. tan(√(10+2)) + cos(3)
+
+17. cos(√(4+1)) * 7
+
+18. tan(10) - √2 / tan(√(10+3)) / 4 / 7^2
+
+19. sin(6) - sin(2) - 1 / √8 - 8
+
+20. tan(3) / cos(5)
\ No newline at end of file
diff --git a/doc/paper/test123/2025-09-28-23-32-54.txt b/doc/paper/test123/2025-09-28-23-32-54.txt
new file mode 100644
index 0000000..5da9266
--- /dev/null
+++ b/doc/paper/test123/2025-09-28-23-32-54.txt
@@ -0,0 +1,5 @@
+1. 66 / 95 + 87
+
+2. (27 / 36 / 19) * 68
+
+3. 1 / 2
\ No newline at end of file
diff --git a/doc/paper/user/2025-09-28-23-33-36.txt b/doc/paper/user/2025-09-28-23-33-36.txt
new file mode 100644
index 0000000..cd20eeb
--- /dev/null
+++ b/doc/paper/user/2025-09-28-23-33-36.txt
@@ -0,0 +1,5 @@
+1. 33
+
+2. 27 + 99 - (24 + 51 / 26)
+
+3. (25 + 26) + 71
\ No newline at end of file
diff --git a/doc/paper/张三1/2025-09-28-22-02-48.txt b/doc/paper/张三1/2025-09-28-22-02-48.txt
new file mode 100644
index 0000000..6ffe6ba
--- /dev/null
+++ b/doc/paper/张三1/2025-09-28-22-02-48.txt
@@ -0,0 +1,31 @@
+1. 39
+
+2. 76 - 14 / 8
+
+3. 49
+
+4. 11 - 76 * (58 / 38 - 73)
+
+5. 16 - 61 * 69
+
+6. (47 / 82 / 65)
+
+7. (62 / 70) / 10
+
+8. 94 * 27 + 50 - 10
+
+9. 44 - (2 + 76 + 58) - 2
+
+10. 27
+
+11. 57 / 60 + 23
+
+12. 90 * 63
+
+13. 72 + 81 + 54 * 1
+
+14. 46 / 92
+
+15. 58 + 12
+
+16. (49 * 19 * 69 * 9)
\ No newline at end of file
diff --git a/doc/paper/张三1/2025-09-28-22-03-02.txt b/doc/paper/张三1/2025-09-28-22-03-02.txt
new file mode 100644
index 0000000..07c7565
--- /dev/null
+++ b/doc/paper/张三1/2025-09-28-22-03-02.txt
@@ -0,0 +1,23 @@
+1. 54
+
+2. 100 / 73 + 69 * 11 / 60
+
+3. 8 + 4 * 40 * 60
+
+4. 91
+
+5. 88 / 58 - 77
+
+6. 2
+
+7. 89 * 87 - 99
+
+8. 89 - 36 + 12
+
+9. 90 / 21
+
+10. 61 - 16 / 93 * 57 * 68
+
+11. 33 * (96 / 45)
+
+12. 14 + (63 + 26)
\ No newline at end of file
diff --git a/doc/paper/张三1/2025-09-28-22-59-11.txt b/doc/paper/张三1/2025-09-28-22-59-11.txt
new file mode 100644
index 0000000..93f214d
--- /dev/null
+++ b/doc/paper/张三1/2025-09-28-22-59-11.txt
@@ -0,0 +1,25 @@
+1. tan(2) / 2 + 6 - √7 - tan(√(2+1))
+
+2. sin(6) * 6^2 / tan(4)
+
+3. sin(1) * cos(10) / √5 + 1
+
+4. tan(√(10+5)) + cos(6) / 10^2 * √6 + 7
+
+5. tan(8) / (4 / 9 + 1)
+
+6. (tan(8) / 9^2 - 6^2 /) 2
+
+7. tan(1) * √6 - sin(7) * 5 * √5
+
+8. cos(8) / cos(8) / √5 - √2 / 10
+
+9. cos(√(1+2)) * 10 / tan(2) / 5 + 3
+
+10. cos(√(1+1)) * 5 + 6 + 6
+
+11. sin(5) * 9^2 - tan(7) / 4 * 10
+
+12. sin(10) / √8 + 8^2 * 6^2 - 5
+
+13. tan(4) * 10
\ No newline at end of file
diff --git a/doc/paper/张三1/2025-09-28-22-59-26.txt b/doc/paper/张三1/2025-09-28-22-59-26.txt
new file mode 100644
index 0000000..041d96b
--- /dev/null
+++ b/doc/paper/张三1/2025-09-28-22-59-26.txt
@@ -0,0 +1,25 @@
+1. √23 * 31
+
+2. 18^2 - 1 + √23 / 18
+
+3. 23^2 - (33 / 25)
+
+4. 27^2 - 9^2
+
+5. √10 - 22^2 * 7
+
+6. 40^2 * √25 * 12 - 16
+
+7. √25 / √1 * 18 * 8 + 32
+
+8. 7^2 / √24 / (50 * 35)
+
+9. 5^2 (* 21 + 35) / 9 * 33
+
+10. √25 - 48^2 + 9
+
+11. 20^2 * 48 + 39
+
+12. √25 / 38 - 21 * 28 * 32
+
+13. 4^2 / √2 * 15
\ No newline at end of file
diff --git a/doc/paper/张三1/2025-09-28-22-59-37.txt b/doc/paper/张三1/2025-09-28-22-59-37.txt
new file mode 100644
index 0000000..e88cec6
--- /dev/null
+++ b/doc/paper/张三1/2025-09-28-22-59-37.txt
@@ -0,0 +1,29 @@
+1. 65 / 18
+
+2. 28 * 78
+
+3. 22 + 93 * 63 * 98
+
+4. 25 - 33 - (35 + 18 / 82)
+
+5. 59
+
+6. 98 + 52 * 94
+
+7. 100 * (87 + 51)
+
+8. (15 / 44 / 55)
+
+9. 37 - 48 * 84
+
+10. 10 * 38
+
+11. 76
+
+12. 67 / (23 * 85)
+
+13. 38 - 100 * 77
+
+14. 94 * 33
+
+15. 38
\ No newline at end of file
diff --git a/doc/paper/张三1/2025-09-29-00-09-16.txt b/doc/paper/张三1/2025-09-29-00-09-16.txt
new file mode 100644
index 0000000..245915c
--- /dev/null
+++ b/doc/paper/张三1/2025-09-29-00-09-16.txt
@@ -0,0 +1,27 @@
+1. 10^2 + 42 - 20
+
+2. √5 * 20
+
+3. (√20 - √25 + 11) / 26 + 29
+
+4. √23 * 6 / 32
+
+5. 31^2 * (35 - √25)
+
+6. √25 + 41 * 11 * 8
+
+7. 48^2 / 7
+
+8. √25 / 17
+
+9. 14^2 / 3
+
+10. √25 / 1 + √3 * 21
+
+11. √25 * (17 / 32^2)
+
+12. 26^2 / 49 - 15^2
+
+13. 43^2 + (49 - 18^2)
+
+14. 49^2 / 27 - 28^2 / 13 + 5
\ No newline at end of file
diff --git a/doc/paper/王五2/2025-09-28-22-26-06.txt b/doc/paper/王五2/2025-09-28-22-26-06.txt
new file mode 100644
index 0000000..494c07b
--- /dev/null
+++ b/doc/paper/王五2/2025-09-28-22-26-06.txt
@@ -0,0 +1,25 @@
+1. cos(1) * 4 * tan(√(6+5)) * 2 / √6
+
+2. cos(10) * sin(√(10+2)) / √1
+
+3. sin(√(3+3)) + sin(√(5+2)) + 6 / 10 + 9
+
+4. cos(√(9+2)) / √1 * 9^2
+
+5. sin(9) + tan(√(2+5))
+
+6. cos(8) - 1 - sin(√(10+2)) + 8
+
+7. tan(2) - 5 + tan(9) / 1
+
+8. tan(3) / 10 * tan(4) + 7 + 7^2
+
+9. tan(√(9+4)) - tan(√(7+4))
+
+10. tan(1) / sin(√(3+2)) / 4
+
+11. tan(10) / 3 * 3 - cos(√(2+5)) * sin(10)
+
+12. sin(3) + √3 / 5
+
+13. tan(5) / cos(7) / sin(√(6+3)) - tan(3) + 2
\ No newline at end of file
diff --git a/src/com/mathpaper/Main.class b/src/com/mathpaper/Main.class
new file mode 100644
index 0000000..d203cca
Binary files /dev/null and b/src/com/mathpaper/Main.class differ
diff --git a/src/com/mathpaper/Main.java b/src/com/mathpaper/Main.java
new file mode 100644
index 0000000..1d74e91
--- /dev/null
+++ b/src/com/mathpaper/Main.java
@@ -0,0 +1,469 @@
+package com.mathpaper;
+
+import com.mathpaper.model.User;
+import com.mathpaper.generator.QuestionGenerator;
+import com.mathpaper.generator.PrimaryGenerator;
+import com.mathpaper.generator.JuniorGenerator;
+import com.mathpaper.generator.SeniorGenerator;
+import com.mathpaper.util.FileUtil;
+import com.mathpaper.util.DuplicateChecker;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Scanner;
+
+/**
+ * 数学试卷生成程序主类
+ * 负责用户登录、交互和试卷生成的主要流程
+ * 
+ * @author 系统
+ * @version 2.0
+ */
+public class Main {
+    
+    // 常量定义
+    private static final int MIN_QUESTIONS = 1;
+    private static final int MAX_QUESTIONS = 100;
+    private static final int PREVIEW_COUNT = 5;
+    private static final int MAX_ATTEMPTS_MULTIPLIER = 10;
+    private static final String GRADE_SWITCH_PREFIX = "切换为";
+    private static final String EXIT_COMMAND = "-1";
+    
+    // 当前年级（全局变量）
+    private static String currentGrade = "小学";
+    
+    // 界面美化常量
+    private static final String SEPARATOR = "=" + "=".repeat(50);
+    private static final String MENU_SEPARATOR = "=" + "=".repeat(50);
+    private static final int PROGRESS_BAR_LENGTH = 30;
+    
+    // 预设用户账号
+    private static final Map<String, User> USERS = new HashMap<>();
+    
+    static {
+        initializeUsers();
+    }
+    
+    /**
+     * 初始化用户账号
+     */
+    private static void initializeUsers() {
+        // 小学用户（中文和英文用户名）
+        addUser("张三1", "123", "小学");
+        addUser("张三2", "123", "小学");
+        addUser("张三3", "123", "小学");
+        addUser("zhangsan1", "123", "小学");
+        addUser("zhangsan2", "123", "小学");
+        addUser("zhangsan3", "123", "小学");
+        addUser("primary1", "123", "小学");
+        addUser("primary2", "123", "小学");
+        
+        // 初中用户（中文和英文用户名）
+        addUser("李四1", "123", "初中");
+        addUser("李四2", "123", "初中");
+        addUser("李四3", "123", "初中");
+        addUser("lisi1", "123", "初中");
+        addUser("lisi2", "123", "初中");
+        addUser("lisi3", "123", "初中");
+        addUser("junior1", "123", "初中");
+        addUser("junior2", "123", "初中");
+        
+        // 高中用户（中文和英文用户名）
+        addUser("王五1", "123", "高中");
+        addUser("王五2", "123", "高中");
+        addUser("王五3", "123", "高中");
+        addUser("wangwu1", "123", "高中");
+        addUser("wangwu2", "123", "高中");
+        addUser("wangwu3", "123", "高中");
+        addUser("senior1", "123", "高中");
+        addUser("senior2", "123", "高中");
+        
+        // 测试账号
+        addUser("test123", "123", "小学");
+        addUser("测试", "123", "小学");
+    }
+    
+    /**
+     * 添加用户到系统
+     */
+    private static void addUser(String username, String password, String grade) {
+        // 由于User类已简化，这里只存储用户名
+        try {
+            USERS.put(username, new User(username));
+        } catch (IllegalArgumentException e) {
+            System.err.println("添加用户失败: " + username + " - " + e.getMessage());
+        }
+    }
+    
+    /**
+     * 程序主入口
+     */
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        
+        try {
+            // 定期清理过期缓存
+            DuplicateChecker.cleanupExpiredCache();
+            
+            // 用户登录
+            User user = performLogin(scanner);
+            if (user == null) {
+                System.out.println("登录失败，程序退出");
+                return;
+            }
+            
+            // 主交互循环
+            runMainLoop(scanner, user);
+            
+        } catch (Exception e) {
+            System.err.println("程序运行出现异常: " + e.getMessage());
+        } finally {
+            scanner.close();
+        }
+    }
+    
+    /**
+     * 用户登录
+     */
+    private static User performLogin(Scanner scanner) {
+        System.out.println("=== 用户登录 ===");
+        System.out.println("请输入用户名和密码进行登录");
+        System.out.println();
+        
+        while (true) {
+            System.out.print("用户名: ");
+            String username = scanner.nextLine().trim();
+            
+            // 验证用户名格式
+            String validationError = User.getValidationError(username);
+            if (validationError != null) {
+                System.out.println("❌ " + validationError);
+                System.out.println("请重新输入：");
+                continue;
+            }
+            
+            // 检查用户是否存在
+            if (!USERS.containsKey(username)) {
+                System.out.println("❌ 用户名不存在，请检查输入或使用以下用户名：");
+                System.out.println("中文用户：张三1, 张三2, 张三3, 李四1, 李四2, 李四3, 王五1, 王五2, 王五3, 测试");
+                System.out.println("英文用户：zhangsan1, zhangsan2, zhangsan3, lisi1, lisi2, lisi3, wangwu1, wangwu2, wangwu3, test123");
+                System.out.println("请重新输入：");
+                continue;
+            }
+            
+            System.out.print("密码: ");
+            String password = scanner.nextLine().trim();
+            
+            // 验证密码（所有用户密码都是123）
+            if (!"123".equals(password)) {
+                System.out.println("❌ 密码错误！所有用户的密码都是 123");
+                System.out.println("请重新输入：");
+                continue;
+            }
+            
+            try {
+                User user = new User(username);
+                System.out.println("✅ 登录成功！欢迎，" + username + "！");
+                System.out.println();
+                return user;
+            } catch (IllegalArgumentException e) {
+                System.out.println("❌ " + e.getMessage());
+                System.out.println("请重新输入：");
+            }
+        }
+    }
+    
+    /**
+     * 验证登录信息（简化版本）
+     */
+    private static User validateLogin(String input) {
+        String[] parts = input.split("\\s+");
+        
+        if (parts.length != 2) {
+            return null;
+        }
+        
+        String username = parts[0].trim();
+        String password = parts[1].trim();
+        
+        // 简单验证：检查用户是否存在
+        User user = USERS.get(username);
+        if (user != null) {
+            return user;
+        }
+        
+        return null;
+    }
+    
+    /**
+     * 运行主交互循环
+     */
+    private static void runMainLoop(Scanner scanner, User user) {
+        QuestionGenerator generator = getGenerator(currentGrade);
+        
+        while (true) {
+            displayMainMenu(user);
+            String choice = scanner.nextLine().trim();
+            
+            switch (choice) {
+                case "1":
+                    handleGradeSwitch(scanner, user);
+                    generator = getGenerator(currentGrade);
+                    break;
+                case "2":
+                    handleQuestionGeneration(scanner, user, generator);
+                    break;
+                case "3":
+                    displayExitMessage();
+                    return;
+                default:
+                    System.out.println("❌ 无效选择，请重新输入！");
+            }
+        }
+    }
+    
+    /**
+     * 显示欢迎界面
+     */
+    private static void displayWelcomeScreen(User user) {
+        System.out.println(SEPARATOR);
+        System.out.println("🎓 数学题目生成系统");
+        System.out.println("👤 用户：" + user.getUsername());
+        System.out.println("📚 当前年级：" + currentGrade);
+        System.out.println(SEPARATOR);
+    }
+    
+    /**
+     * 显示主菜单
+     */
+    private static void displayMainMenu(User user) {
+        System.out.println(MENU_SEPARATOR);
+        System.out.println("📚 当前年级：" + currentGrade);
+        System.out.println("👤 当前用户：" + user.getUsername());
+        System.out.println();
+        System.out.println("1. 切换年级");
+        System.out.println("2. 生成试卷");
+        System.out.println("3. 退出系统");
+        System.out.println(MENU_SEPARATOR);
+        System.out.print("\n🔹 请选择操作（当前：" + currentGrade + "）：");
+    }
+    
+    /**
+     * 显示分隔线
+     */
+    private static void displaySeparator() {
+        System.out.println("\n" + "-".repeat(30) + "\n");
+    }
+    
+    /**
+     * 显示退出消息
+     */
+    private static void displayExitMessage() {
+        System.out.println("\n" + SEPARATOR);
+        System.out.println("👋 感谢使用数学题目生成系统！");
+        System.out.println("🎉 祝您学习愉快，再见！");
+        System.out.println(SEPARATOR);
+    }
+    
+    /**
+     * 根据年级获取对应的题目生成器
+     */
+    private static QuestionGenerator getGenerator(String grade) {
+        switch (grade) {
+            case "小学":
+                return new PrimaryGenerator();
+            case "初中":
+                return new JuniorGenerator();
+            case "高中":
+                return new SeniorGenerator();
+            default:
+                System.err.println("未知年级: " + grade + "，使用小学模式");
+                return new PrimaryGenerator();
+        }
+    }
+    
+    /**
+     * 验证年级是否有效
+     */
+    private static boolean isValidGrade(String grade) {
+        return "小学".equals(grade) || "初中".equals(grade) || "高中".equals(grade);
+    }
+    
+    /**
+     * 生成并保存试卷
+     */
+    private static void generateAndSavePaper(QuestionGenerator generator, int count, User user) {
+        try {
+            List<String> questions = generateQuestionsWithProgress(generator, count, user.getUsername());
+            
+            if (questions.isEmpty()) {
+                System.out.println("❌ 生成失败：无法生成题目，请稍后重试");
+                return;
+            }
+            
+            if (questions.size() < count) {
+                System.out.println("⚠️  注意：由于查重限制，实际生成了 " + questions.size() + " 道题目");
+            }
+            
+            System.out.print("💾 正在保存试卷...");
+            String path = FileUtil.getSavePath(user.getUsername());
+            FileUtil.savePaper(path, questions);
+            System.out.println(" 完成！");
+            System.out.println("✅ 试卷已保存至：" + path);
+            
+            displayQuestionPreview(questions);
+            
+        } catch (Exception e) {
+            System.err.println("❌ 生成试卷时出现错误: " + e.getMessage());
+        }
+    }
+    
+    /**
+     * 带进度提示的题目生成
+     */
+    private static List<String> generateQuestionsWithProgress(QuestionGenerator generator, int count, String username) {
+        List<String> questions = new ArrayList<>();
+        generator.clearCurrentQuestions();
+        
+        int attempts = 0;
+        int maxAttempts = count * MAX_ATTEMPTS_MULTIPLIER;
+        
+        System.out.println("📊 生成进度：");
+        
+        while (questions.size() < count && attempts < maxAttempts) {
+            try {
+                String question = generator.generateUniqueQuestion();
+                
+                if (question != null && !question.trim().isEmpty()) {
+                    // 检查是否与历史题目重复
+                    if (!DuplicateChecker.isDuplicate(question, username)) {
+                        questions.add(question);
+                        
+                        // 显示进度
+                        displayProgress(questions.size(), count);
+                    }
+                }
+                
+            } catch (Exception e) {
+                System.err.println("⚠️  生成题目时出现错误: " + e.getMessage());
+            }
+            
+            attempts++;
+        }
+        
+        if (questions.size() < count && attempts >= maxAttempts) {
+            System.out.println("\n⚠️  提示：已达到最大尝试次数，可能存在题目重复过多的情况");
+        } else if (questions.size() == count) {
+            System.out.println("\n🎉 题目生成完成！");
+        }
+        
+        return questions;
+    }
+    
+    /**
+     * 显示生成进度
+     */
+    private static void displayProgress(int current, int total) {
+        int percentage = (int) ((double) current / total * 100);
+        int progressLength = (int) ((double) current / total * PROGRESS_BAR_LENGTH);
+        
+        StringBuilder progressBar = new StringBuilder();
+        progressBar.append("[");
+        
+        for (int i = 0; i < PROGRESS_BAR_LENGTH; i++) {
+            if (i < progressLength) {
+                progressBar.append("█");
+            } else {
+                progressBar.append("░");
+            }
+        }
+        
+        progressBar.append("]");
+        
+        System.out.print("\r" + progressBar.toString() + " " + current + "/" + total + " (" + percentage + "%)");
+        
+        if (current == total) {
+            System.out.println(); // 换行
+        }
+    }
+    
+    /**
+     * 显示题目预览
+     */
+    private static void displayQuestionPreview(List<String> questions) {
+        System.out.println("\n📝 题目预览");
+        System.out.println("─".repeat(40));
+        
+        int displayCount = Math.min(PREVIEW_COUNT, questions.size());
+        for (int i = 0; i < displayCount; i++) {
+            System.out.println((i + 1) + ". " + questions.get(i));
+        }
+        
+        if (questions.size() > PREVIEW_COUNT) {
+            System.out.println("   ... 还有 " + (questions.size() - PREVIEW_COUNT) + " 道题目");
+        }
+        
+        System.out.println("─".repeat(40));
+        System.out.println("📊 总计：" + questions.size() + " 道题目");
+    }
+    
+    /**
+     * 处理年级切换
+     */
+    private static void handleGradeSwitch(Scanner scanner, User user) {
+        System.out.println("\n📚 请选择年级：");
+        System.out.println("1. 小学");
+        System.out.println("2. 初中");
+        System.out.println("3. 高中");
+        System.out.print("请输入选择（1-3）：");
+        
+        String choice = scanner.nextLine().trim();
+        String newGrade = null;
+        
+        switch (choice) {
+            case "1":
+                newGrade = "小学";
+                break;
+            case "2":
+                newGrade = "初中";
+                break;
+            case "3":
+                newGrade = "高中";
+                break;
+            default:
+                System.out.println("❌ 无效选择！");
+                return;
+        }
+        
+        if (!newGrade.equals(currentGrade)) {
+            currentGrade = newGrade;
+            System.out.println("✅ 已切换到" + currentGrade + "模式");
+        } else {
+            System.out.println("ℹ️ 当前已是" + currentGrade + "模式");
+        }
+    }
+    
+    /**
+     * 处理题目生成
+     */
+    private static void handleQuestionGeneration(Scanner scanner, User user, QuestionGenerator generator) {
+        System.out.print("\n📝 请输入要生成的题目数量（1-50）：");
+        String input = scanner.nextLine().trim();
+        
+        try {
+            int count = Integer.parseInt(input);
+            if (count < 1 || count > 50) {
+                System.out.println("❌ 题目数量必须在1-50之间！");
+                return;
+            }
+            
+            System.out.println("\n🔄 开始生成" + count + "道" + currentGrade + "数学题目...");
+            generateAndSavePaper(generator, count, user);
+            
+        } catch (NumberFormatException e) {
+            System.out.println("❌ 请输入有效的数字！");
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/com/mathpaper/generator/JuniorGenerator.class b/src/com/mathpaper/generator/JuniorGenerator.class
new file mode 100644
index 0000000..3296504
Binary files /dev/null and b/src/com/mathpaper/generator/JuniorGenerator.class differ
diff --git a/src/com/mathpaper/generator/JuniorGenerator.java b/src/com/mathpaper/generator/JuniorGenerator.java
new file mode 100644
index 0000000..e1f6d72
--- /dev/null
+++ b/src/com/mathpaper/generator/JuniorGenerator.java
@@ -0,0 +1,151 @@
+package com.mathpaper.generator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 初中题目生成器
+ * 生成2-5个操作数的题目，至少含1个平方（^2）或开根号（√），支持嵌套括号
+ * 
+ * @author 系统
+ * @version 2.0
+ */
+public class JuniorGenerator extends QuestionGenerator {
+    
+    // 常量定义
+    private static final int MIN_OPERANDS = 2;
+    private static final int MAX_OPERANDS = 5;
+    private static final int MIN_NUMBER = 1;
+    private static final int MAX_NUMBER = 50; // 避免数字过大
+    private static final String[] OPERATORS = {"+", "-", "*", "/"};
+    private static final double ADVANCED_OP_PROBABILITY = 0.3; // 30%概率添加高级运算
+    private static final double BRACKET_PROBABILITY = 0.4; // 40%概率添加括号
+    
+    /**
+     * 构造函数
+     */
+    public JuniorGenerator() {
+        super("初中");
+    }
+    
+    @Override
+    public String generateQuestion() {
+        int numCount = randomInt(MIN_OPERANDS, MAX_OPERANDS);
+        List<Integer> nums = generateNumbers(numCount);
+        List<String> ops = generateOperators(numCount - 1);
+        return addAdvancedOperations(nums, ops);
+    }
+    
+    /**
+     * 生成指定数量的随机数（1-50，避免过大）
+     * @param count 数字数量
+     * @return 数字列表
+     */
+    private List<Integer> generateNumbers(int count) {
+        List<Integer> nums = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) {
+            nums.add(randomInt(MIN_NUMBER, MAX_NUMBER));
+        }
+        return nums;
+    }
+    
+    /**
+     * 生成指定数量的运算符
+     * @param count 运算符数量
+     * @return 运算符列表
+     */
+    private List<String> generateOperators(int count) {
+        List<String> ops = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) {
+            ops.add(randomChoice(OPERATORS));
+        }
+        return ops;
+    }
+    
+    /**
+     * 添加高级运算（平方、开根号）和嵌套括号
+     * @param nums 数字列表
+     * @param ops 运算符列表
+     * @return 包含高级运算的表达式字符串
+     */
+    private String addAdvancedOperations(List<Integer> nums, List<String> ops) {
+        StringBuilder sb = new StringBuilder(nums.size() * 12); // 预估容量
+        
+        // 确保至少有一个平方或开根号
+        boolean hasAdvanced = false;
+        int advancedCount = 0;
+        
+        for (int i = 0; i < nums.size(); i++) {
+            int num = nums.get(i);
+            
+            // 决定是否添加高级运算
+            boolean shouldAddAdvanced = !hasAdvanced || 
+                (advancedCount < 2 && random.nextDouble() < ADVANCED_OP_PROBABILITY);
+            
+            if (shouldAddAdvanced) {
+                if (random.nextBoolean()) {
+                    // 添加平方
+                    sb.append(num).append("^2");
+                } else {
+                    // 添加开根号（选择较小的数避免复杂计算）
+                    int sqrtNum = Math.min(num, 25); // 限制开根号的数不超过25
+                    sb.append("√").append(sqrtNum);
+                }
+                hasAdvanced = true;
+                advancedCount++;
+            } else {
+                sb.append(num);
+            }
+            
+            if (i < ops.size()) {
+                sb.append(" ").append(ops.get(i)).append(" ");
+            }
+        }
+        
+        // 添加嵌套括号
+        return addNestedBrackets(sb.toString());
+    }
+    
+    /**
+     * 添加嵌套括号
+     * @param expression 原始表达式
+     * @return 带括号的表达式
+     */
+    private String addNestedBrackets(String expression) {
+        if (random.nextDouble() >= BRACKET_PROBABILITY) {
+            return expression;
+        }
+        
+        String[] parts = expression.split(" ");
+        if (parts.length < 3) {
+            return expression;
+        }
+        
+        // 选择括号范围（确保至少包含一个完整的运算）
+        int maxStart = parts.length - 3; // 至少需要 数字 运算符 数字
+        int start = randomInt(0, maxStart);
+        int minEnd = start + 2; // 至少包含3个部分
+        int maxEnd = Math.min(start + 6, parts.length - 1); // 最多包含7个部分
+        int end = randomInt(minEnd, maxEnd);
+        
+        StringBuilder result = new StringBuilder(expression.length() + 4);
+        
+        for (int i = 0; i < parts.length; i++) {
+            if (i == start) {
+                result.append("(");
+            }
+            
+            result.append(parts[i]);
+            
+            if (i == end) {
+                result.append(")");
+            }
+            
+            if (i < parts.length - 1) {
+                result.append(" ");
+            }
+        }
+        
+        return result.toString();
+    }
+}
\ No newline at end of file
diff --git a/src/com/mathpaper/generator/PrimaryGenerator.class b/src/com/mathpaper/generator/PrimaryGenerator.class
new file mode 100644
index 0000000..b5aad32
Binary files /dev/null and b/src/com/mathpaper/generator/PrimaryGenerator.class differ
diff --git a/src/com/mathpaper/generator/PrimaryGenerator.java b/src/com/mathpaper/generator/PrimaryGenerator.java
new file mode 100644
index 0000000..c3357b0
--- /dev/null
+++ b/src/com/mathpaper/generator/PrimaryGenerator.java
@@ -0,0 +1,130 @@
+package com.mathpaper.generator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 小学题目生成器
+ * 生成1-5个操作数的四则运算题目，支持最多1层括号
+ * 
+ * @author 系统
+ * @version 2.0
+ */
+public class PrimaryGenerator extends QuestionGenerator {
+    
+    // 常量定义
+    private static final int MIN_OPERANDS = 1;
+    private static final int MAX_OPERANDS = 5;
+    private static final int MIN_NUMBER = 1;
+    private static final int MAX_NUMBER = 100;
+    private static final String[] OPERATORS = {"+", "-", "*", "/"};
+    private static final double BRACKET_PROBABILITY = 0.5; // 50%概率添加括号
+    
+    /**
+     * 构造函数
+     */
+    public PrimaryGenerator() {
+        super("小学");
+    }
+    
+    @Override
+    public String generateQuestion() {
+        int numCount = randomInt(MIN_OPERANDS, MAX_OPERANDS);
+        List<Integer> nums = generateNumbers(numCount);
+        List<String> ops = generateOperators(numCount - 1);
+        return addBrackets(nums, ops);
+    }
+    
+    /**
+     * 生成指定数量的随机数（1-100）
+     * @param count 数字数量
+     * @return 数字列表
+     */
+    private List<Integer> generateNumbers(int count) {
+        List<Integer> nums = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) {
+            nums.add(randomInt(MIN_NUMBER, MAX_NUMBER));
+        }
+        return nums;
+    }
+    
+    /**
+     * 生成指定数量的运算符
+     * @param count 运算符数量
+     * @return 运算符列表
+     */
+    private List<String> generateOperators(int count) {
+        List<String> ops = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) {
+            ops.add(randomChoice(OPERATORS));
+        }
+        return ops;
+    }
+    
+    /**
+     * 添加括号（最多1层，无嵌套）
+     * @param nums 数字列表
+     * @param ops 运算符列表
+     * @return 带括号的表达式字符串
+     */
+    private String addBrackets(List<Integer> nums, List<String> ops) {
+        // 随机决定是否添加括号（需要至少3个操作数）
+        if (nums.size() >= 3 && random.nextDouble() < BRACKET_PROBABILITY) {
+            return addSimpleBrackets(nums, ops);
+        }
+        
+        return buildBasicExpression(nums, ops);
+    }
+    
+    /**
+     * 构建基本表达式（无括号）
+     * @param nums 数字列表
+     * @param ops 运算符列表
+     * @return 表达式字符串
+     */
+    private String buildBasicExpression(List<Integer> nums, List<String> ops) {
+        StringBuilder sb = new StringBuilder(nums.size() * 8); // 预估容量
+        
+        for (int i = 0; i < nums.size(); i++) {
+            sb.append(nums.get(i));
+            if (i < ops.size()) {
+                sb.append(" ").append(ops.get(i)).append(" ");
+            }
+        }
+        
+        return sb.toString();
+    }
+    
+    /**
+     * 添加简单括号（不嵌套）
+     * @param nums 数字列表
+     * @param ops 运算符列表
+     * @return 带括号的表达式字符串
+     */
+    private String addSimpleBrackets(List<Integer> nums, List<String> ops) {
+        StringBuilder sb = new StringBuilder(nums.size() * 10); // 预估容量（包含括号）
+        
+        // 随机选择括号位置（确保至少包含2个操作数）
+        int maxStart = nums.size() - 2;
+        int bracketStart = randomInt(0, maxStart);
+        int bracketEnd = randomInt(bracketStart + 1, nums.size() - 1);
+        
+        for (int i = 0; i < nums.size(); i++) {
+            if (i == bracketStart) {
+                sb.append("(");
+            }
+            
+            sb.append(nums.get(i));
+            
+            if (i == bracketEnd) {
+                sb.append(")");
+            }
+            
+            if (i < ops.size()) {
+                sb.append(" ").append(ops.get(i)).append(" ");
+            }
+        }
+        
+        return sb.toString();
+    }
+}
\ No newline at end of file
diff --git a/src/com/mathpaper/generator/QuestionGenerator.class b/src/com/mathpaper/generator/QuestionGenerator.class
new file mode 100644
index 0000000..1a42a0e
Binary files /dev/null and b/src/com/mathpaper/generator/QuestionGenerator.class differ
diff --git a/src/com/mathpaper/generator/QuestionGenerator.java b/src/com/mathpaper/generator/QuestionGenerator.java
new file mode 100644
index 0000000..be5244a
--- /dev/null
+++ b/src/com/mathpaper/generator/QuestionGenerator.java
@@ -0,0 +1,194 @@
+package com.mathpaper.generator;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.Random;
+import java.util.concurrent.ThreadLocalRandom;
+
+/**
+ * 题目生成器抽象基类
+ * 定义题目生成的基本结构和通用方法
+ * 
+ * @author 系统
+ * @version 2.0
+ */
+public abstract class QuestionGenerator {
+    
+    // 常量定义
+    protected static final int MAX_GENERATION_ATTEMPTS = 50;
+    protected static final int INITIAL_SET_CAPACITY = 64;
+    
+    protected final String grade;
+    protected final Set<String> currentQuestions; // 本次生成的题目（防重复）
+    protected final Random random;
+    
+    // 性能统计
+    private int totalAttempts = 0;
+    private int successfulGenerations = 0;
+    
+    /**
+     * 构造函数
+     * @param grade 年级
+     */
+    public QuestionGenerator(String grade) {
+        if (grade == null || grade.trim().isEmpty()) {
+            throw new IllegalArgumentException("年级不能为空");
+        }
+        
+        this.grade = grade.trim();
+        this.currentQuestions = new HashSet<>(INITIAL_SET_CAPACITY);
+        this.random = ThreadLocalRandom.current(); // 使用线程安全的随机数生成器
+    }
+    
+    /**
+     * 抽象方法：生成一道题目
+     * 子类必须实现此方法
+     * @return 生成的题目字符串
+     */
+    public abstract String generateQuestion();
+    
+    /**
+     * 生成不重复的题目（优化版本）
+     * @return 生成的题目字符串，如果无法生成返回null
+     */
+    public String generateUniqueQuestion() {
+        String question = null;
+        int attempts = 0;
+        
+        while (attempts < MAX_GENERATION_ATTEMPTS) {
+            try {
+                question = generateQuestion();
+                totalAttempts++;
+                
+                if (question != null && !question.trim().isEmpty()) {
+                    String normalizedQuestion = normalizeQuestion(question);
+                    
+                    if (!currentQuestions.contains(normalizedQuestion)) {
+                        currentQuestions.add(normalizedQuestion);
+                        successfulGenerations++;
+                        return question;
+                    }
+                }
+                
+            } catch (Exception e) {
+                System.err.println("生成题目时发生错误: " + e.getMessage());
+            }
+            
+            attempts++;
+        }
+        
+        // 如果达到最大尝试次数仍未成功，记录警告
+        if (attempts >= MAX_GENERATION_ATTEMPTS) {
+            System.err.println("警告：" + grade + "题目生成器达到最大尝试次数(" + MAX_GENERATION_ATTEMPTS + ")");
+        }
+        
+        return question; // 返回最后一次生成的题目，即使可能重复
+    }
+    
+    /**
+     * 标准化题目格式，用于重复检查
+     * @param question 原始题目
+     * @return 标准化后的题目
+     */
+    protected String normalizeQuestion(String question) {
+        if (question == null) {
+            return "";
+        }
+        
+        return question.trim()
+                      .replaceAll("\\s+", " ") // 统一空格
+                      .toLowerCase(); // 转小写（如果需要）
+    }
+    
+    /**
+     * 清空当前题目集合
+     */
+    public void clearCurrentQuestions() {
+        currentQuestions.clear();
+        // 重置统计信息
+        totalAttempts = 0;
+        successfulGenerations = 0;
+    }
+    
+    /**
+     * 获取年级
+     * @return 年级字符串
+     */
+    public String getGrade() {
+        return grade;
+    }
+    
+    /**
+     * 获取当前已生成的题目数量
+     * @return 题目数量
+     */
+    public int getCurrentQuestionCount() {
+        return currentQuestions.size();
+    }
+    
+    /**
+     * 检查题目是否已存在
+     * @param question 要检查的题目
+     * @return 如果题目已存在返回true
+     */
+    public boolean isQuestionExists(String question) {
+        if (question == null || question.trim().isEmpty()) {
+            return false;
+        }
+        
+        String normalized = normalizeQuestion(question);
+        return currentQuestions.contains(normalized);
+    }
+    
+    /**
+     * 获取生成效率统计
+     * @return 成功率（0.0-1.0）
+     */
+    public double getGenerationEfficiency() {
+        if (totalAttempts == 0) {
+            return 0.0;
+        }
+        return (double) successfulGenerations / totalAttempts;
+    }
+    
+    /**
+     * 获取统计信息字符串
+     * @return 统计信息
+     */
+    public String getStatistics() {
+        return String.format("生成器统计[%s]: 总尝试=%d, 成功=%d, 效率=%.2f%%", 
+                           grade, totalAttempts, successfulGenerations, 
+                           getGenerationEfficiency() * 100);
+    }
+    
+    /**
+     * 生成指定范围内的随机整数（包含边界）
+     * @param min 最小值
+     * @param max 最大值
+     * @return 随机整数
+     */
+    protected int randomInt(int min, int max) {
+        if (min > max) {
+            throw new IllegalArgumentException("最小值不能大于最大值");
+        }
+        
+        if (min == max) {
+            return min;
+        }
+        
+        return random.nextInt(max - min + 1) + min;
+    }
+    
+    /**
+     * 从数组中随机选择一个元素
+     * @param array 数组
+     * @return 随机选择的元素
+     */
+    protected <T> T randomChoice(T[] array) {
+        if (array == null || array.length == 0) {
+            throw new IllegalArgumentException("数组不能为空");
+        }
+        
+        return array[random.nextInt(array.length)];
+    }
+}
\ No newline at end of file
diff --git a/src/com/mathpaper/generator/SeniorGenerator.class b/src/com/mathpaper/generator/SeniorGenerator.class
new file mode 100644
index 0000000..66e8b4e
Binary files /dev/null and b/src/com/mathpaper/generator/SeniorGenerator.class differ
diff --git a/src/com/mathpaper/generator/SeniorGenerator.java b/src/com/mathpaper/generator/SeniorGenerator.java
new file mode 100644
index 0000000..83e199c
--- /dev/null
+++ b/src/com/mathpaper/generator/SeniorGenerator.java
@@ -0,0 +1,216 @@
+package com.mathpaper.generator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 高中题目生成器
+ * 生成2-5个操作数的题目，至少含1个sin/cos/tan（弧度制），支持函数嵌套
+ * 
+ * @author 系统
+ * @version 2.0
+ */
+public class SeniorGenerator extends QuestionGenerator {
+    
+    // 常量定义
+    private static final int MIN_OPERANDS = 2;
+    private static final int MAX_OPERANDS = 5;
+    private static final int MIN_NUMBER = 1;
+    private static final int MAX_NUMBER = 10; // 避免过大的弧度值
+    private static final String[] OPERATORS = {"+", "-", "*", "/"};
+    private static final String[] TRIG_FUNCTIONS = {"sin", "cos", "tan"};
+    private static final double TRIG_PROBABILITY = 0.4; // 40%概率添加三角函数
+    private static final double NESTED_PROBABILITY = 0.3; // 30%概率函数嵌套
+    private static final double ADVANCED_OP_PROBABILITY = 0.3; // 30%概率添加高级运算
+    private static final double BRACKET_PROBABILITY = 0.3; // 30%概率添加括号
+    
+    /**
+     * 构造函数
+     */
+    public SeniorGenerator() {
+        super("高中");
+    }
+    
+    @Override
+    public String generateQuestion() {
+        int numCount = randomInt(MIN_OPERANDS, MAX_OPERANDS);
+        List<Integer> nums = generateNumbers(numCount);
+        List<String> ops = generateOperators(numCount - 1);
+        return addTrigonometricFunctions(nums, ops);
+    }
+    
+    /**
+     * 生成指定数量的随机数（1-10，避免过大的弧度值）
+     * @param count 数字数量
+     * @return 数字列表
+     */
+    private List<Integer> generateNumbers(int count) {
+        List<Integer> nums = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) {
+            nums.add(randomInt(MIN_NUMBER, MAX_NUMBER));
+        }
+        return nums;
+    }
+    
+    /**
+     * 生成指定数量的运算符
+     * @param count 运算符数量
+     * @return 运算符列表
+     */
+    private List<String> generateOperators(int count) {
+        List<String> ops = new ArrayList<>(count);
+        for (int i = 0; i < count; i++) {
+            ops.add(randomChoice(OPERATORS));
+        }
+        return ops;
+    }
+    
+    /**
+     * 添加三角函数和函数嵌套
+     * @param nums 数字列表
+     * @param ops 运算符列表
+     * @return 包含三角函数的表达式字符串
+     */
+    private String addTrigonometricFunctions(List<Integer> nums, List<String> ops) {
+        StringBuilder sb = new StringBuilder(nums.size() * 15); // 预估容量
+        
+        // 确保至少有一个三角函数
+        boolean hasTrig = false;
+        int trigCount = 0;
+        
+        for (int i = 0; i < nums.size(); i++) {
+            int num = nums.get(i);
+            
+            // 决定是否添加三角函数
+            boolean shouldAddTrig = !hasTrig || 
+                (trigCount < 2 && random.nextDouble() < TRIG_PROBABILITY);
+            
+            if (shouldAddTrig) {
+                String func = randomChoice(TRIG_FUNCTIONS);
+                
+                // 决定是否嵌套函数
+                if (random.nextDouble() < NESTED_PROBABILITY) {
+                    // 函数嵌套，如 sin(√(5+3))
+                    int innerNum = randomInt(1, 5);
+                    sb.append(func).append("(√(").append(num)
+                      .append("+").append(innerNum).append("))");
+                } else {
+                    // 简单函数，如 sin(3)
+                    sb.append(func).append("(").append(num).append(")");
+                }
+                hasTrig = true;
+                trigCount++;
+            } else {
+                // 添加其他高级运算或普通数字
+                if (random.nextDouble() < ADVANCED_OP_PROBABILITY) {
+                    if (random.nextBoolean()) {
+                        sb.append(num).append("^2");
+                    } else {
+                        // 限制开根号的数值避免过于复杂
+                        int sqrtNum = Math.min(num, 9);
+                        sb.append("√").append(sqrtNum);
+                    }
+                } else {
+                    sb.append(num);
+                }
+            }
+            
+            if (i < ops.size()) {
+                sb.append(" ").append(ops.get(i)).append(" ");
+            }
+        }
+        
+        // 添加复杂括号
+        return addComplexBrackets(sb.toString());
+    }
+    
+    /**
+     * 添加复杂括号结构
+     * @param expression 原始表达式
+     * @return 带括号的表达式
+     */
+    private String addComplexBrackets(String expression) {
+        // 如果表达式中已有函数调用的括号，减少额外括号的概率
+        boolean hasFunctionBrackets = expression.contains("sin(") || 
+                                    expression.contains("cos(") || 
+                                    expression.contains("tan(");
+        
+        double actualBracketProb = hasFunctionBrackets ? 
+                                  BRACKET_PROBABILITY * 0.5 : BRACKET_PROBABILITY;
+        
+        if (random.nextDouble() >= actualBracketProb) {
+            return expression;
+        }
+        
+        String[] parts = expression.split(" ");
+        if (parts.length < 5) {
+            return expression;
+        }
+        
+        // 选择括号范围，避免破坏函数调用结构
+        int maxStart = parts.length - 4;
+        int start = randomInt(0, maxStart);
+        int minEnd = start + 3;
+        int maxEnd = Math.min(start + 5, parts.length - 1);
+        int end = randomInt(minEnd, maxEnd);
+        
+        // 检查是否会破坏函数调用结构
+        StringBuilder testBuilder = new StringBuilder();
+        for (int i = start; i <= end; i++) {
+            testBuilder.append(parts[i]);
+            if (i < end) testBuilder.append(" ");
+        }
+        String testSection = testBuilder.toString();
+        
+        // 如果选中的部分包含不完整的函数调用，跳过添加括号
+        if (containsIncompleteFunction(testSection)) {
+            return expression;
+        }
+        
+        StringBuilder result = new StringBuilder(expression.length() + 4);
+        
+        for (int i = 0; i < parts.length; i++) {
+            if (i == start) {
+                result.append("(");
+            }
+            
+            result.append(parts[i]);
+            
+            if (i == end) {
+                result.append(")");
+            }
+            
+            if (i < parts.length - 1) {
+                result.append(" ");
+            }
+        }
+        
+        return result.toString();
+    }
+    
+    /**
+     * 检查字符串是否包含不完整的函数调用
+     * @param text 要检查的文本
+     * @return 如果包含不完整的函数调用返回true
+     */
+    private boolean containsIncompleteFunction(String text) {
+        for (String func : TRIG_FUNCTIONS) {
+            if (text.contains(func + "(") && !text.contains(")")) {
+                return true;
+            }
+            if (text.contains(")") && !text.contains(func + "(")) {
+                // 检查是否有孤立的右括号
+                int leftCount = 0;
+                int rightCount = 0;
+                for (char c : text.toCharArray()) {
+                    if (c == '(') leftCount++;
+                    if (c == ')') rightCount++;
+                }
+                if (rightCount > leftCount) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/src/com/mathpaper/model/User.class b/src/com/mathpaper/model/User.class
new file mode 100644
index 0000000..af09c72
Binary files /dev/null and b/src/com/mathpaper/model/User.class differ
diff --git a/src/com/mathpaper/model/User.java b/src/com/mathpaper/model/User.java
new file mode 100644
index 0000000..52de919
--- /dev/null
+++ b/src/com/mathpaper/model/User.java
@@ -0,0 +1,118 @@
+package com.mathpaper.model;
+
+import java.util.regex.Pattern;
+
+/**
+ * 用户实体类
+ * 表示系统中的用户信息
+ * 
+ * @author 系统
+ * @version 2.0
+ */
+public class User {
+    
+    // 用户名验证正则表达式：允许字母、数字、下划线和中文字符，长度2-20
+    private static final Pattern USERNAME_PATTERN = Pattern.compile("^[a-zA-Z0-9_\\u4e00-\\u9fa5]{2,20}$");
+    
+    // 用户名长度限制
+    private static final int MIN_USERNAME_LENGTH = 2;
+    private static final int MAX_USERNAME_LENGTH = 20;
+    
+    private String username;
+    
+    /**
+     * 构造函数
+     * @param username 用户名
+     * @throws IllegalArgumentException 如果用户名无效
+     */
+    public User(String username) {
+        setUsername(username);
+    }
+    
+    /**
+     * 获取用户名
+     * @return 用户名
+     */
+    public String getUsername() {
+        return username;
+    }
+    
+    /**
+     * 设置用户名（带验证）
+     * @param username 用户名
+     * @throws IllegalArgumentException 如果用户名无效
+     */
+    public void setUsername(String username) {
+        if (!isValidUsername(username)) {
+            throw new IllegalArgumentException("用户名无效：必须是2-20位字母、数字、下划线或中文字符");
+        }
+        this.username = username.trim();
+    }
+    
+    /**
+     * 验证用户名是否有效
+     * @param username 要验证的用户名
+     * @return 如果用户名有效返回true，否则返回false
+     */
+    public static boolean isValidUsername(String username) {
+        if (username == null || username.trim().isEmpty()) {
+            return false;
+        }
+        
+        String trimmed = username.trim();
+        
+        // 检查长度
+        if (trimmed.length() < MIN_USERNAME_LENGTH || trimmed.length() > MAX_USERNAME_LENGTH) {
+            return false;
+        }
+        
+        // 检查格式
+        return USERNAME_PATTERN.matcher(trimmed).matches();
+    }
+    
+    /**
+     * 获取用户名验证错误信息
+     * @param username 要验证的用户名
+     * @return 错误信息，如果用户名有效则返回null
+     */
+    public static String getValidationError(String username) {
+        if (username == null || username.trim().isEmpty()) {
+            return "用户名不能为空";
+        }
+        
+        String trimmed = username.trim();
+        
+        if (trimmed.length() < MIN_USERNAME_LENGTH) {
+            return "用户名长度不能少于" + MIN_USERNAME_LENGTH + "位";
+        }
+        
+        if (trimmed.length() > MAX_USERNAME_LENGTH) {
+            return "用户名长度不能超过" + MAX_USERNAME_LENGTH + "位";
+        }
+        
+        if (!USERNAME_PATTERN.matcher(trimmed).matches()) {
+            return "用户名只能包含字母、数字、下划线和中文字符";
+        }
+        
+        return null; // 验证通过
+    }
+    
+    @Override
+    public String toString() {
+        return "User{username='" + username + "'}";
+    }
+    
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        
+        User user = (User) obj;
+        return username != null ? username.equals(user.username) : user.username == null;
+    }
+    
+    @Override
+    public int hashCode() {
+        return username != null ? username.hashCode() : 0;
+    }
+}
\ No newline at end of file
diff --git a/src/com/mathpaper/util/DuplicateChecker.class b/src/com/mathpaper/util/DuplicateChecker.class
new file mode 100644
index 0000000..e04e51c
Binary files /dev/null and b/src/com/mathpaper/util/DuplicateChecker.class differ
diff --git a/src/com/mathpaper/util/DuplicateChecker.java b/src/com/mathpaper/util/DuplicateChecker.java
new file mode 100644
index 0000000..8531601
--- /dev/null
+++ b/src/com/mathpaper/util/DuplicateChecker.java
@@ -0,0 +1,281 @@
+package com.mathpaper.util;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * 查重工具类
+ * 负责检查题目是否在历史文件中重复
+ * 
+ * @author 系统
+ * @version 2.0
+ */
+public class DuplicateChecker {
+    
+    // 缓存用户的历史题目，提高查重性能
+    private static final ConcurrentHashMap<String, Set<String>> userQuestionCache = new ConcurrentHashMap<>();
+    
+    // 缓存的最大用户数，防止内存溢出
+    private static final int MAX_CACHED_USERS = 10;
+    
+    // 缓存访问时间记录，用于LRU清理
+    private static final ConcurrentHashMap<String, Long> cacheAccessTime = new ConcurrentHashMap<>();
+    
+    // 缓存清理阈值（毫秒）
+    private static final long CACHE_EXPIRY_TIME = 30 * 60 * 1000; // 30分钟
+    
+    /**
+     * 检查题目是否在历史文件中存在
+     * @param question 要检查的题目
+     * @param username 用户名
+     * @return 如果题目重复返回true，否则返回false
+     */
+    public static boolean isDuplicate(String question, String username) {
+        if (question == null || question.trim().isEmpty()) {
+            return false;
+        }
+        
+        if (username == null || username.trim().isEmpty()) {
+            return false;
+        }
+        
+        try {
+            String cleanQuestion = cleanQuestionText(question);
+            Set<String> userQuestions = getUserQuestions(username);
+            return userQuestions.contains(cleanQuestion);
+            
+        } catch (Exception e) {
+            System.err.println("查重检查时发生错误: " + e.getMessage());
+            return false; // 出错时默认不重复，避免阻塞题目生成
+        }
+    }
+    
+    /**
+     * 获取用户的所有历史题目（带缓存）
+     */
+    private static Set<String> getUserQuestions(String username) {
+        // 检查缓存
+        Set<String> cachedQuestions = userQuestionCache.get(username);
+        if (cachedQuestions != null) {
+            // 更新访问时间
+            cacheAccessTime.put(username, System.currentTimeMillis());
+            return cachedQuestions;
+        }
+        
+        // 缓存未命中，从文件加载
+        Set<String> questions = loadUserQuestionsFromFiles(username);
+        
+        // 缓存管理：如果缓存已满，清理最久未使用的条目
+        if (userQuestionCache.size() >= MAX_CACHED_USERS) {
+            cleanupOldestCache();
+        }
+        
+        // 添加到缓存
+        userQuestionCache.put(username, questions);
+        cacheAccessTime.put(username, System.currentTimeMillis());
+        
+        return questions;
+    }
+    
+    /**
+     * 从文件加载用户的历史题目
+     */
+    private static Set<String> loadUserQuestionsFromFiles(String username) {
+        Set<String> questions = new HashSet<>();
+        
+        try {
+            String userDir = FileUtil.getUserPaperDir(username);
+            Path userPath = Paths.get(userDir);
+            
+            if (!Files.exists(userPath)) {
+                return questions;
+            }
+            
+            // 使用NIO遍历用户目录下的所有文件
+            Files.walk(userPath)
+                .filter(Files::isRegularFile)
+                .filter(path -> path.toString().endsWith(".txt"))
+                .forEach(path -> {
+                    try {
+                        Files.lines(path, StandardCharsets.UTF_8)
+                            .map(String::trim)
+                            .filter(line -> !line.isEmpty())
+                            .map(DuplicateChecker::cleanQuestionText)
+                            .forEach(questions::add);
+                    } catch (IOException e) {
+                        System.err.println("读取文件失败: " + path + " - " + e.getMessage());
+                    }
+                });
+                
+        } catch (Exception e) {
+            System.err.println("加载用户题目失败: " + e.getMessage());
+        }
+        
+        return questions;
+    }
+    
+    /**
+     * 清理最久未使用的缓存条目
+     */
+    private static void cleanupOldestCache() {
+        if (cacheAccessTime.isEmpty()) {
+            return;
+        }
+        
+        // 找到最久未访问的用户
+        String oldestUser = cacheAccessTime.entrySet().stream()
+            .min((e1, e2) -> Long.compare(e1.getValue(), e2.getValue()))
+            .map(entry -> entry.getKey())
+            .orElse(null);
+            
+        if (oldestUser != null) {
+            userQuestionCache.remove(oldestUser);
+            cacheAccessTime.remove(oldestUser);
+        }
+    }
+    
+    /**
+     * 定期清理过期缓存
+     */
+    public static void cleanupExpiredCache() {
+        long currentTime = System.currentTimeMillis();
+        
+        cacheAccessTime.entrySet().removeIf(entry -> {
+            if (currentTime - entry.getValue() > CACHE_EXPIRY_TIME) {
+                userQuestionCache.remove(entry.getKey());
+                return true;
+            }
+            return false;
+        });
+    }
+    
+    /**
+     * 从单个文件加载题目
+     */
+    private static void loadQuestionsFromFile(Path filePath, Set<String> questions) {
+        try (BufferedReader reader = Files.newBufferedReader(filePath, StandardCharsets.UTF_8)) {
+            String line;
+            while ((line = reader.readLine()) != null) {
+                String cleanLine = cleanQuestionText(line);
+                if (!cleanLine.isEmpty()) {
+                    questions.add(cleanLine);
+                }
+            }
+        } catch (IOException e) {
+            System.err.println("读取文件时发生错误: " + filePath + " - " + e.getMessage());
+        }
+    }
+    
+    /**
+     * 清理题目文本，统一格式用于比较
+     * @param text 原始文本
+     * @return 清理后的题目内容
+     */
+    private static String cleanQuestionText(String text) {
+        if (text == null || text.trim().isEmpty()) {
+            return "";
+        }
+        
+        String cleaned = text.trim();
+        
+        // 去除题号（如"1. "、"2) "等格式）
+        cleaned = cleaned.replaceFirst("^\\d+[.)、]\\s*", "");
+        
+        // 去除多余的空白字符
+        cleaned = cleaned.replaceAll("\\s+", " ").trim();
+        
+        return cleaned;
+    }
+    
+    /**
+     * 批量检查题目列表是否有重复
+     * @param questions 题目列表
+     * @param username 用户名
+     * @return 重复的题目数量
+     */
+    public static int countDuplicates(String[] questions, String username) {
+        if (questions == null || questions.length == 0) {
+            return 0;
+        }
+        
+        if (username == null || username.trim().isEmpty()) {
+            return 0;
+        }
+        
+        int duplicateCount = 0;
+        try {
+            for (String question : questions) {
+                if (isDuplicate(question, username)) {
+                    duplicateCount++;
+                }
+            }
+        } catch (Exception e) {
+            System.err.println("批量查重时发生错误: " + e.getMessage());
+        }
+        
+        return duplicateCount;
+    }
+    
+    /**
+     * 获取用户历史试卷文件数量
+     * @param username 用户名
+     * @return 历史试卷文件数量
+     */
+    public static int getHistoryFileCount(String username) {
+        if (username == null || username.trim().isEmpty()) {
+            return 0;
+        }
+        
+        try {
+            String userDir = FileUtil.getUserPaperDir(username);
+            Path dirPath = Paths.get(userDir);
+            
+            if (!Files.exists(dirPath) || !Files.isDirectory(dirPath)) {
+                return 0;
+            }
+            
+            return (int) Files.list(dirPath)
+                .filter(path -> Files.isRegularFile(path))
+                .filter(path -> path.toString().endsWith(".txt"))
+                .count();
+                
+        } catch (IOException e) {
+            System.err.println("获取历史文件数量时发生错误: " + e.getMessage());
+            return 0;
+        }
+    }
+    
+    /**
+     * 清理指定用户的缓存
+     * @param username 用户名
+     */
+    public static void clearUserCache(String username) {
+        if (username != null) {
+            userQuestionCache.remove(username);
+        }
+    }
+    
+    /**
+     * 清理所有缓存
+     */
+    public static void clearAllCache() {
+        userQuestionCache.clear();
+    }
+    
+    /**
+     * 获取当前缓存的用户数量（用于监控）
+     * @return 缓存的用户数量
+     */
+    public static int getCachedUserCount() {
+        return userQuestionCache.size();
+    }
+}
\ No newline at end of file
diff --git a/src/com/mathpaper/util/FileUtil.class b/src/com/mathpaper/util/FileUtil.class
new file mode 100644
index 0000000..0d88b4d
Binary files /dev/null and b/src/com/mathpaper/util/FileUtil.class differ
diff --git a/src/com/mathpaper/util/FileUtil.java b/src/com/mathpaper/util/FileUtil.java
new file mode 100644
index 0000000..838daa7
--- /dev/null
+++ b/src/com/mathpaper/util/FileUtil.java
@@ -0,0 +1,290 @@
+package com.mathpaper.util;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * 文件操作工具类
+ * 负责试卷文件的保存和路径处理
+ * 
+ * @author 系统
+ * @version 2.1 - 优化资源管理和性能
+ */
+public class FileUtil {
+    
+    // 基础目录常量
+    private static final String BASE_DIR = "doc";
+    private static final String PAPER_DIR = "paper";
+    private static final String FILE_EXTENSION = ".txt";
+    
+    // 性能优化常量
+    private static final int BUFFER_SIZE = 8192; // 8KB缓冲区
+    private static final int MAX_FILENAME_LENGTH = 255;
+    
+    // 时间戳格式
+    private static final SimpleDateFormat TIMESTAMP_FORMAT = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
+    
+    /**
+     * 生成保存路径：doc/paper/用户名/时间戳.txt
+     * @param username 用户名
+     * @return 文件保存路径
+     * @throws IllegalArgumentException 如果用户名无效
+     */
+    public static String getSavePath(String username) {
+        validateUsername(username);
+        
+        try {
+            String sanitizedUsername = sanitizeFilename(username.trim());
+            Path userDir = Paths.get(BASE_DIR, PAPER_DIR, sanitizedUsername);
+            
+            // 确保目录存在
+            Files.createDirectories(userDir);
+            
+            String timestamp = TIMESTAMP_FORMAT.format(new Date());
+            Path filePath = userDir.resolve(timestamp + FILE_EXTENSION);
+            
+            return filePath.toString();
+            
+        } catch (IOException e) {
+            System.err.println("创建保存路径时发生错误: " + e.getMessage());
+            // 降级到传统方式
+            return getFallbackSavePath(username);
+        }
+    }
+    
+    /**
+     * 验证用户名
+     */
+    private static void validateUsername(String username) {
+        if (username == null || username.trim().isEmpty()) {
+            throw new IllegalArgumentException("用户名不能为空");
+        }
+        if (username.trim().length() > MAX_FILENAME_LENGTH) {
+            throw new IllegalArgumentException("用户名过长");
+        }
+    }
+    
+    /**
+     * 降级保存路径生成方法
+     */
+    private static String getFallbackSavePath(String username) {
+        String sanitizedUsername = sanitizeFilename(username.trim());
+        String baseDir = BASE_DIR + File.separator + PAPER_DIR + File.separator + sanitizedUsername;
+        File dir = new File(baseDir);
+        if (!dir.exists() && !dir.mkdirs()) {
+            throw new RuntimeException("无法创建目录: " + baseDir);
+        }
+        
+        String timestamp = TIMESTAMP_FORMAT.format(new Date());
+        return baseDir + File.separator + timestamp + FILE_EXTENSION;
+    }
+    
+    /**
+     * 清理文件名中的非法字符
+     */
+    private static String sanitizeFilename(String filename) {
+        if (filename == null) {
+            return "default";
+        }
+        
+        // 替换Windows文件名中的非法字符
+        String sanitized = filename.replaceAll("[<>:\"/\\\\|?*]", "_")
+                                  .replaceAll("\\s+", "_")
+                                  .trim();
+        
+        // 确保文件名不为空且不超过最大长度
+        if (sanitized.isEmpty()) {
+            sanitized = "default";
+        }
+        if (sanitized.length() > MAX_FILENAME_LENGTH) {
+            sanitized = sanitized.substring(0, MAX_FILENAME_LENGTH);
+        }
+        
+        return sanitized;
+    }
+    
+    /**
+     * 保存试卷到文件（带题号和空行）
+     * @param path 文件路径
+     * @param questions 题目列表
+     * @throws IllegalArgumentException 如果参数无效
+     * @throws RuntimeException 如果保存失败
+     */
+    public static void savePaper(String path, List<String> questions) {
+        validateSaveParameters(path, questions);
+        
+        try {
+            Path filePath = Paths.get(path);
+            
+            // 确保父目录存在
+            Path parentDir = filePath.getParent();
+            if (parentDir != null) {
+                Files.createDirectories(parentDir);
+            }
+            
+            // 使用NIO写入文件，指定UTF-8编码和缓冲区大小
+            try (BufferedWriter writer = Files.newBufferedWriter(filePath, StandardCharsets.UTF_8,
+                    StandardOpenOption.CREATE, StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING)) {
+                
+                writeQuestionsToFile(writer, questions);
+            }
+            
+        } catch (IOException e) {
+            System.err.println("保存文件时发生错误: " + e.getMessage());
+            // 尝试降级保存
+            savePaperFallback(path, questions);
+        } catch (Exception e) {
+            System.err.println("保存试卷时发生未知错误: " + e.getMessage());
+            throw new RuntimeException("保存试卷失败", e);
+        }
+    }
+    
+    /**
+     * 验证保存参数
+     */
+    private static void validateSaveParameters(String path, List<String> questions) {
+        if (path == null || path.trim().isEmpty()) {
+            throw new IllegalArgumentException("文件路径不能为空");
+        }
+        if (questions == null || questions.isEmpty()) {
+            throw new IllegalArgumentException("题目列表不能为空");
+        }
+    }
+    
+    /**
+     * 将题目写入文件
+     */
+    private static void writeQuestionsToFile(BufferedWriter writer, List<String> questions) throws IOException {
+        for (int i = 0; i < questions.size(); i++) {
+            String question = questions.get(i);
+            if (question != null && !question.trim().isEmpty()) {
+                writer.write((i + 1) + ". " + question.trim());
+                
+                // 题间空一行，但最后一题不加空行
+                if (i < questions.size() - 1) {
+                    writer.newLine();
+                    writer.newLine();
+                }
+            }
+        }
+        writer.flush();
+    }
+    
+    /**
+     * 降级保存方法（使用传统IO）
+     */
+    private static void savePaperFallback(String path, List<String> questions) {
+        try (BufferedWriter bw = new BufferedWriter(
+                new java.io.FileWriter(path, StandardCharsets.UTF_8), BUFFER_SIZE)) {
+            
+            writeQuestionsToFile(bw, questions);
+            
+        } catch (IOException e) {
+            System.err.println("降级保存也失败: " + e.getMessage());
+            throw new RuntimeException("文件保存完全失败", e);
+        }
+    }
+    
+    /**
+     * 检查文件是否存在
+     * @param path 文件路径
+     * @return 文件是否存在
+     */
+    public static boolean fileExists(String path) {
+        if (path == null || path.trim().isEmpty()) {
+            return false;
+        }
+        
+        try {
+            Path filePath = Paths.get(path);
+            return Files.exists(filePath) && Files.isRegularFile(filePath);
+        } catch (Exception e) {
+            // 降级到传统方式
+            File file = new File(path);
+            return file.exists() && file.isFile();
+        }
+    }
+    
+    /**
+     * 创建目录
+     * @param dirPath 目录路径
+     * @return 是否创建成功
+     */
+    public static boolean createDirectory(String dirPath) {
+        if (dirPath == null || dirPath.trim().isEmpty()) {
+            return false;
+        }
+        
+        try {
+            Path path = Paths.get(dirPath);
+            Files.createDirectories(path);
+            return true;
+        } catch (IOException e) {
+            System.err.println("创建目录失败: " + e.getMessage());
+            // 降级到传统方式
+            File dir = new File(dirPath);
+            return dir.mkdirs() || dir.exists();
+        }
+    }
+    
+    /**
+     * 获取用户试卷目录
+     * @param username 用户名
+     * @return 用户试卷目录路径
+     */
+    public static String getUserPaperDir(String username) {
+        if (username == null || username.trim().isEmpty()) {
+            throw new IllegalArgumentException("用户名不能为空");
+        }
+        
+        String sanitizedUsername = sanitizeFilename(username.trim());
+        return BASE_DIR + File.separator + PAPER_DIR + File.separator + sanitizedUsername;
+    }
+    
+    /**
+     * 获取文件大小（字节）
+     * @param path 文件路径
+     * @return 文件大小，如果文件不存在返回-1
+     */
+    public static long getFileSize(String path) {
+        if (path == null || path.trim().isEmpty()) {
+            return -1;
+        }
+        
+        try {
+            Path filePath = Paths.get(path);
+            return Files.exists(filePath) ? Files.size(filePath) : -1;
+        } catch (IOException e) {
+            System.err.println("获取文件大小失败: " + e.getMessage());
+            return -1;
+        }
+    }
+    
+    /**
+     * 删除文件
+     * @param path 文件路径
+     * @return 是否删除成功
+     */
+    public static boolean deleteFile(String path) {
+        if (path == null || path.trim().isEmpty()) {
+            return false;
+        }
+        
+        try {
+            Path filePath = Paths.get(path);
+            return Files.deleteIfExists(filePath);
+        } catch (IOException e) {
+            System.err.println("删除文件失败: " + e.getMessage());
+            return false;
+        }
+    }
+}
\ No newline at end of file
diff --git a/start.bat b/start.bat
new file mode 100644
index 0000000..4d8ac97
--- /dev/null
+++ b/start.bat
@@ -0,0 +1,6 @@
+@echo off
+REM Convenience startup script - redirects to the main startup script
+REM 便捷启动脚本 - 重定向到主启动脚本
+
+echo Redirecting to main startup script...
+call "doc\bin\start.bat"
\ No newline at end of file
diff --git a/start.ps1 b/start.ps1
new file mode 100644
index 0000000..1d51490
--- /dev/null
+++ b/start.ps1
@@ -0,0 +1,5 @@
+# Convenience startup script - redirects to the main startup script
+# 便捷启动脚本 - 重定向到主启动脚本
+
+Write-Host "Redirecting to main startup script..." -ForegroundColor Yellow
+& ".\doc\bin\start.ps1"
\ No newline at end of file