重构：删除没有被使用的代码

早期规划该项目时，功能多于当前实现。删除的是当前无用的代码，例如根据班级名称查找所有学生等。后期如果完善该项目，可以查看该commit删除的代码

src/dao/StudentDAO.java

@@ -14,13 +14,6 @@ public interface StudentDAO extends BaseDAO<Student> {
      */
     Student findByStudentId(String studentId);
 
-    /**
-     * 根据班级查询学生列表
-     * @param className 班级名称
-     * @return 学生列表
-     */
-    List<Student> findByClassName(String className);
-
     /**
      * 根据姓名模糊查询学生
      * @param name 学生姓名

src/dao/TeacherDAO.java

@@ -13,18 +13,4 @@ public interface TeacherDAO extends BaseDAO<Teacher> {
      * @return 教师对象
      */
     Teacher findByTeacherId(String teacherId);
-
-    /**
-     * 根据部门查询教师列表
-     * @param department 部门名称
-     * @return 教师列表
-     */
-    List<Teacher> findByDepartment(String department);
-
-    /**
-     * 根据姓名模糊查询教师
-     * @param name 教师姓名
-     * @return 教师列表
-     */
-    List<Teacher> findByNameLike(String name);
 }

src/dao/impl/StudentDAOImpl.java

@@ -133,25 +133,6 @@ public class StudentDAOImpl implements StudentDAO {
         return null;
     }
 
-    @Override
-    public List<Student> findByClassName(String className) {
-        List<Student> students = new ArrayList<>();
-        String sql = "SELECT * FROM students WHERE class_name = ?";
-        try (Connection conn = DatabaseUtil.getConnection();
-             PreparedStatement stmt = conn.prepareStatement(sql)) {
-            
-            stmt.setString(1, className);
-            ResultSet rs = stmt.executeQuery();
-            
-            while (rs.next()) {
-                students.add(mapResultSetToStudent(rs));
-            }
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-        return students;
-    }
-
     @Override
     public List<Student> findByNameLike(String name) {
         List<Student> students = new ArrayList<>();

src/dao/impl/TeacherDAOImpl.java

@@ -129,44 +129,6 @@ public class TeacherDAOImpl implements TeacherDAO {
         return null;
     }
 
-    @Override
-    public List<Teacher> findByDepartment(String department) {
-        List<Teacher> teachers = new ArrayList<>();
-        String sql = "SELECT * FROM teachers WHERE department = ?";
-        try (Connection conn = DatabaseUtil.getConnection();
-             PreparedStatement stmt = conn.prepareStatement(sql)) {
-            
-            stmt.setString(1, department);
-            ResultSet rs = stmt.executeQuery();
-            
-            while (rs.next()) {
-                teachers.add(mapResultSetToTeacher(rs));
-            }
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-        return teachers;
-    }
-
-    @Override
-    public List<Teacher> findByNameLike(String name) {
-        List<Teacher> teachers = new ArrayList<>();
-        String sql = "SELECT * FROM teachers WHERE name LIKE ?";
-        try (Connection conn = DatabaseUtil.getConnection();
-             PreparedStatement stmt = conn.prepareStatement(sql)) {
-            
-            stmt.setString(1, "%" + name + "%");
-            ResultSet rs = stmt.executeQuery();
-            
-            while (rs.next()) {
-                teachers.add(mapResultSetToTeacher(rs));
-            }
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-        return teachers;
-    }
-
     /**
      * 将ResultSet映射为Teacher对象
      */