Problem_Generator/src/Generator.java

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

/**
 * 题目生成器，支持历史查重和文件保存
 */
public class Generator {
  
  //生成题目并保存到用户文件夹
  public static void generate(Users users, int count, ProblemsGenerator problemsGenerator) {
    Set<String> history = loadHistory(users);
    StringBuilder builder = new StringBuilder();
    
    for (int i = 1; i <= count; i++) {
      String problem;
      int tries = 0;
      do {
        problem = problemsGenerator.generate();
        tries++;
        if (tries >= 20) {
          System.out.println("警告：尝试 20 次仍未生成新题目，可能题目库有限。");
          break;
        }
      } while (history.contains(problem));
      
      history.add(problem);
      builder.append(i).append(". ").append(problem).append("\n\n");
    }
    
    save(users, builder.toString());
    System.out.println("题目生成完成。");
  }
  
  /**
   * 读取用户历史题目
   */
  private static Set<String> loadHistory(Users users) {
    Set<String> history = new HashSet<>();
    String safeName = users.getName().replaceAll("[^\\u4e00-\\u9fa5a-zA-Z0-9_]", "_");
    String folder = "doc/" + safeName;
    File dir = new File(folder);
    if (!dir.exists()) return history;
    
    File[] files = dir.listFiles((d, name) -> name.endsWith(".txt"));
    if (files != null) {
      for (File f : files) {
        try (Scanner sc = new Scanner(f)) {
          while (sc.hasNextLine()) {
            String line = sc.nextLine().trim();
            if (!line.isEmpty() && Character.isDigit(line.charAt(0))) {
              int dot = line.indexOf('.');
              if (dot != -1) line = line.substring(dot + 1).trim();
              history.add(line);
            }
          }
        } catch (IOException e) {
          e.printStackTrace();
          System.out.println("读取历史题目失败：" + e.getMessage());
        }
      }
    }
    
    return history;
  }
  
  /**
   * 保存生成题目到文件
   */
  private static void save(Users users, String content) {
    try {
      String safeName = users.getName().replaceAll("[^\\u4e00-\\u9fa5a-zA-Z0-9_]", "_");
      String folder = "doc/" + safeName;
      File dir = new File(folder);
      if (!dir.exists() && !dir.mkdirs()) {
        System.out.println("无法创建目录: " + folder);
        return;
      }
      
      String filename = LocalDateTime.now()
          .format(DateTimeFormatter.ofPattern("yyyy-MM-dd-HH-mm-ss"))
          + "-" + (int) (Math.random() * 1000) + ".txt";
      
      try (FileWriter writer = new FileWriter(folder + "/" + filename)) {
        writer.write(content);
      }
    } catch (IOException e) {
      e.printStackTrace();
      System.out.println("保存失败：" + e.getMessage());
    }
  }
}