肖海南学生管理分页查询优化

src/main/java/com/teaching/backend/service/courses/ICoursesService.java

@@ -54,7 +54,7 @@ public interface ICoursesService extends IService<Courses> {
     List<PersonalCenterStudentListVO> queryStudentList(String userId);
     LinkedHashSet<UmsStudentManage> queryTeacherByStudentLearningRecordList(String userId);
 
-    LinkedHashSet<UmsStudentManage> queryTeacherByStudentList(String userId);
+    List<UmsStudentManage> queryTeacherByStudentList(String userId);
 
     List<CourseUserInfVO> getUserInfByCourse(Long userId);
 }

src/main/java/com/teaching/backend/service/impl/courses/CoursesServiceImpl.java

@@ -407,25 +407,28 @@ public class CoursesServiceImpl extends ServiceImpl<CoursesMapper, Courses> impl
     }
 
     @Override
-    public LinkedHashSet<UmsStudentManage> queryTeacherByStudentList(String userId) {
+    public List<UmsStudentManage> queryTeacherByStudentList(String userId) {
         String roleId = umsUserMapper.getByIdRoleId(userId);
         CourseQuery courseQuery = new CourseQuery();
         courseQuery.setUserId(userId);
-        LinkedHashSet<UmsStudentManage> umsStudentManageList = new LinkedHashSet<>();
         if (roleId.equals("1")){
-            PageDTO<CoursesVO> queryCourses = queryCourses(courseQuery);
+            PageDTO<CoursesVO> queryCourses = queryForTeacher(courseQuery);
             List<CoursesVO> coursesList = queryCourses.getList();
-            List<String> courseIds = coursesList.stream().map(CoursesVO::getId).collect(Collectors.toList());
-            for (String courseId : courseIds) {
-                List<StudentCourses> studentUsernames = studentCoursesMapper.selectBatchSomeStudent(courseId);
-                for (StudentCourses studentUsername : studentUsernames) {
-                    UmsStudentManage umsStudentManage = umsStudentManageMapper.queryStudent(String.valueOf(studentUsername.getStudent()));
-                    if (umsStudentManage != null){
-                        umsStudentManageList.add(umsStudentManage);
-                    }
-                }
-            }
-            return umsStudentManageList;
+
+            // 首先，收集所有需要查询的学生ID
+            Set<Long> studentIds = coursesList.stream()
+                    .map(CoursesVO::getId)
+                    .flatMap(courseId -> studentCoursesMapper.selectBatchSomeStudent(courseId).stream()
+                            .map(StudentCourses::getStudent)) // 假设getStudent返回Long类型
+                    .collect(Collectors.toSet()); // 使用Set去重
+
+            // 然后，一次性查询所有学生信息
+            List<UmsStudentManage> umsStudentManageLists = studentIds.stream()
+                    .map(studentId -> umsStudentManageMapper.queryStudent(String.valueOf(studentId))) // 假设queryStudent接受Long类型参数
+                    .filter(Objects::nonNull)
+                    .collect(Collectors.toList());
+
+            return umsStudentManageLists;
         }
         throw new BusinessException(400,"只有老师才有此功能");
     }

src/main/java/com/teaching/backend/service/impl/umsAdmin/UmsStudentManageServiceImpl.java

@@ -54,7 +54,7 @@ public class UmsStudentManageServiceImpl extends ServiceImpl<UmsStudentManageMap
     @Override
     public Map<String, Object> pageQuery(UmsStudentPageQueryDTO umsStudentPageQueryDTO) {
 
-        LinkedHashSet<UmsStudentManage> umsStudentManages = coursesService.queryTeacherByStudentList(umsStudentPageQueryDTO.getUserId());
+        List<UmsStudentManage> umsStudentManages = coursesService.queryTeacherByStudentList(umsStudentPageQueryDTO.getUserId());
 
         //总记录数
         int totalCount = umsStudentManages.size();