From fb4f781e56382ce006d00be602d52d0849030eff Mon Sep 17 00:00:00 2001
From: Spark <2666652@gmail.com>
Date: Sat, 12 Oct 2024 00:51:01 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E5=AE=8C=E6=88=90=E7=82=B9=E5=90=8D?=
 =?UTF-8?q?=E5=8A=9F=E8=83=BD?=
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---
 .../aspark/controller/StudentController.java  | 13 ++++++
 .../cc/aspark/service/StudentService.java     |  3 ++
 .../service/impl/StudentServiceImpl.java      | 43 +++++++++++++++++++
 3 files changed, 59 insertions(+)

diff --git a/RollCallServer/src/main/java/cc/aspark/controller/StudentController.java b/RollCallServer/src/main/java/cc/aspark/controller/StudentController.java
index dc5d436..1928f49 100644
--- a/RollCallServer/src/main/java/cc/aspark/controller/StudentController.java
+++ b/RollCallServer/src/main/java/cc/aspark/controller/StudentController.java
@@ -84,5 +84,18 @@ public class StudentController {
         return Result.success();
     }
 
+    @Operation(summary = "随机抽取一名学生")
+    @GetMapping("/rollcall")
+    public Result<Student> rollCall() {
+        Student stu = studentService.rollCall();
+        return Result.success(stu);
+    }
+
+    @Operation(summary = "更新积分")
+    @PutMapping("/points/{id}/{points}")
+    public Result updatePoints(@PathVariable Integer id, @PathVariable Double points) {
+        studentService.updatePoints(id, points);
+        return Result.success();
+    }
 
 }
diff --git a/RollCallServer/src/main/java/cc/aspark/service/StudentService.java b/RollCallServer/src/main/java/cc/aspark/service/StudentService.java
index 81e3a40..4b1086a 100644
--- a/RollCallServer/src/main/java/cc/aspark/service/StudentService.java
+++ b/RollCallServer/src/main/java/cc/aspark/service/StudentService.java
@@ -21,8 +21,11 @@ public interface StudentService extends IService<Student> {
 
     void save(StudentDTO studentDTO);
 
+    Student rollCall();
+
     void importStudentsByExcel(MultipartFile file);
 
     void exportStudentsToExcel(HttpServletResponse response);
 
+    void updatePoints(Integer id, Double points);
 }
diff --git a/RollCallServer/src/main/java/cc/aspark/service/impl/StudentServiceImpl.java b/RollCallServer/src/main/java/cc/aspark/service/impl/StudentServiceImpl.java
index 5cf98c4..4bc4207 100644
--- a/RollCallServer/src/main/java/cc/aspark/service/impl/StudentServiceImpl.java
+++ b/RollCallServer/src/main/java/cc/aspark/service/impl/StudentServiceImpl.java
@@ -127,6 +127,43 @@ public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student>
         baseMapper.insert(student);
     }
 
+    @Override
+    public Student rollCall() {
+        List<Student> studentList = this.list();
+
+        if (studentList.isEmpty()) {
+            throw new RuntimeException("学生列表为空");
+        }
+
+        // 找出最高积分，用于计算反向权重
+        final double maxPoints = studentList.stream()
+                .mapToDouble(Student::getPoints)
+                .max()
+                .orElse(0.0) + 1.0;
+
+        // 计算总的反向权重
+        double totalInverseWeights = studentList.stream()
+                .mapToDouble(student -> maxPoints - student.getPoints())
+                .sum();
+
+        // 生成一个0到总反向权重之间的随机数
+        Random random = new Random();
+        double randomValue = random.nextDouble() * totalInverseWeights;
+
+        // 使用累加器方法选择学生
+        double accumulatedWeight = 0;
+        for (Student student : studentList) {
+            // 计算该学生的反向权重
+            double inverseWeight = maxPoints - student.getPoints();
+            accumulatedWeight += inverseWeight;
+            if (accumulatedWeight >= randomValue) {
+                return student;
+            }
+        }
+
+        // 以防万一，返回最后一个学生
+        return studentList.get(studentList.size() - 1);
+    }
 
     @Override
     public void importStudentsByExcel(MultipartFile file) {
@@ -232,4 +269,10 @@ public class StudentServiceImpl extends ServiceImpl<StudentMapper, Student>
         }
     }
 
+    @Override
+    public void updatePoints(Integer id, Double points) {
+        Student student = baseMapper.selectById(id);
+        student.setPoints(student.getPoints() + points);
+        baseMapper.updateById(student);
+    }
 }
\ No newline at end of file