采用javaee实现服务层，定义教师查询，班级查询，学生查询相关接口，并实现对应接口

好的，以下是针对您要求的实现方式：

首先，在服务层定义教师查询、班级查询、学生查询相关接口，示例代码如下：

public interface TeacherService {
    List<Teacher> getAllTeachers();
    Teacher getTeacherById(int id);
    List<Teacher> getTeachersByDepartment(String department);
}

public interface ClassService {
    List<Class> getAllClasses();
    Class getClassById(int id);
    List<Class> getClassesByDepartment(String department);
}

public interface StudentService {
    List<Student> getAllStudents();
    Student getStudentById(int id);
    List<Student> getStudentsByClass(int classId);
}

接着，实现上述接口，可以使用MyBatis框架来访问数据库并获取数据，示例代码如下：

@Service
public class TeacherServiceImpl implements TeacherService {
    @Autowired
    private TeacherMapper teacherMapper;
    
    @Override
    public List<Teacher> getAllTeachers() {
        return teacherMapper.getAllTeachers();
    }
    
    @Override
    public Teacher getTeacherById(int id) {
        return teacherMapper.getTeacherById(id);
    }
    
    @Override
    public List<Teacher> getTeachersByDepartment(String department) {
        return teacherMapper.getTeachersByDepartment(department);
    }
}

@Service
public class ClassServiceImpl implements ClassService {
    @Autowired
    private ClassMapper classMapper;
    
    @Override
    public List<Class> getAllClasses() {
        return classMapper.getAllClasses();
    }
    
    @Override
    public Class getClassById(int id) {
        return classMapper.getClassById(id);
    }
    
    @Override
    public List<Class> getClassesByDepartment(String department) {
        return classMapper.getClassesByDepartment(department);
    }
}

@Service
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentMapper studentMapper;
    
    @Override
    public List<Student> getAllStudents() {
        return studentMapper.getAllStudents();
    }
    
    @Override
    public Student getStudentById(int id) {
        return studentMapper.getStudentById(id);
    }
    
    @Override
    public List<Student> getStudentsByClass(int classId) {
        return studentMapper.getStudentsByClass(classId);
    }
}

最后，在Controller中注入上述服务层，并编写相应的请求处理方法，示例代码如下：

@RestController
@RequestMapping("/api")
public class ApiController {
    @Autowired
    private TeacherService teacherService;
    
    @Autowired
    private ClassService classService;
    
    @Autowired
    private StudentService studentService;
    
    @GetMapping("/teachers")
    public List<Teacher> getAllTeachers() {
        return teacherService.getAllTeachers();
    }
    
    @GetMapping("/teachers/{id}")
    public Teacher getTeacherById(@PathVariable int id) {
        return teacherService.getTeacherById(id);
    }
    
    @GetMapping("/teachers/department/{department}")
    public List<Teacher> getTeachersByDepartment(@PathVariable String department) {
        return teacherService.getTeachersByDepartment(department);
    }
    
    @GetMapping("/classes")
    public List<Class> getAllClasses() {
        return classService.getAllClasses();
    }
    
    @GetMapping("/classes/{id}")
    public Class getClassById(@PathVariable int id) {
        return classService.getClassById(id);
    }
    
    @GetMapping("/classes/department/{department}")
    public List<Class> getClassesByDepartment(@PathVariable String department) {
        return classService.getClassesByDepartment(department);
    }
    
    @GetMapping("/students")
    public List<Student> getAllStudents() {
        return studentService.getAllStudents();
    }
    
    @GetMapping("/students/{id}")
    public Student getStudentById(@PathVariable int id) {
        return studentService.getStudentById(id);
    }
    
    @GetMapping("/students/class/{classId}")
    public List<Student> getStudentsByClass(@PathVariable int classId) {
        return studentService.getStudentsByClass(classId);
    }
}

以上代码仅供参考，具体实现方式还需要根据实际需求进行调整。