编辑代码

package service;

import dao.GradeDAO;
import model.Grade;

public class GradeService {
    private GradeDAO gradeDao = new GradeDAO();
    
    // 录入成绩（教师）
    public boolean inputGrade(Grade grade) {
        return gradeDao.inputGrade(grade);
    }
    
    // 获取学生成绩
    public List<Grade> getStudentGrades(String studentId) {
        return gradeDao.getGradesByStudent(studentId);
    }
    
    // 获取课程成绩
    public List<Grade> getCourseGrades(String courseId) {
        return gradeDao.getGradesByCourse(courseId);
    }
    
    // 退回成绩（管理员）
    public boolean returnGrade(int gradeId) {
        return gradeDao.updateGradeStatus(gradeId, "returned");
    }
}