Done With Controller Code

src/main/java/com/school/project/controller/CourseController.java

 package com.school.project.controller;
 
+import com.school.project.dto.CourseDTO;
+import com.school.project.mapper.CourseMapper;
 import com.school.project.model.Course;
+import com.school.project.service.implementation.CourseServiceImp;
 import com.school.project.service.interfaces.CourseService;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.dao.EmptyResultDataAccessException;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.*;
 
+import java.sql.SQLIntegrityConstraintViolationException;
 import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.Optional;
 
-
 @Controller
 @RequestMapping()
 public class CourseController {
     @Autowired(required = true)
-    public CourseService courseService;
+    public CourseServiceImp courseServiceImpl;
+
+    @PostMapping("/courses")
+    public ResponseEntity<CourseDTO> saveCourse(@RequestBody CourseDTO courseDTO) {
+
+        try {
+            CourseDTO course = courseServiceImpl.saveCourse(courseDTO);
+            return ResponseEntity.status(HttpStatus.OK).body(course);
+        } catch (Exception e) {
 
-    @PostMapping("/course")
-    public Course saveCourse(@RequestBody Course course){
-        return courseService.saveCourse(course);
+            return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
+        }
     }
 
     @GetMapping("/courses")
-    public List<Course> readAllCourses(){
-       return courseService.readAllCourse();
+    public ResponseEntity<List<CourseDTO>> readAllCourses() {
+        List<CourseDTO> course = courseServiceImpl.readAllCourse();
+
+        if (course.size() <= 0) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
+        } else {
+            return ResponseEntity.status(HttpStatus.OK).body(course);
+        }
     }
 
-    @GetMapping("/course/{id}")
-    public Optional<Course> readCourseById(@PathVariable(name = "id") Long id)
-    {
-        return courseService.readCourseById(id);
+    @GetMapping("/courses/{id}")
+    public ResponseEntity<CourseDTO> readCourseById(@PathVariable(name = "id") Long id) {
+
+        try {
+            CourseDTO course = courseServiceImpl.readCourseById(id);
+            return ResponseEntity.status(HttpStatus.OK).body(course);
+        } catch (NoSuchElementException e) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
+        }
+
     }
 
-    @PutMapping("/course/{id}")
-    public Course updateCourseById(@RequestBody Course course,@PathVariable(name = "id") Long id){
-        return courseService.updateCourseById(course,id);
+    @PutMapping("/courses/{id}")
+    public ResponseEntity<CourseDTO> updateCourseById(@RequestBody CourseDTO courseDTO, @PathVariable(name = "id") Long id) {
+        try {
+            CourseDTO updateCourse = courseServiceImpl.updateCourseById(courseDTO, id);
+            return ResponseEntity.status(HttpStatus.OK).body(updateCourse);
+
+        } catch (NoSuchElementException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
+
     }
 
-    @DeleteMapping("/course/{id}")
-    public void deleteCourseById(@PathVariable(name = "id") Long id){
-        courseService.deleteCourseById(id);
+    @DeleteMapping("/courses/{id}")
+    public ResponseEntity deleteCourseById(@PathVariable(name = "id") Long id) {
+
+        try {
+            courseServiceImpl.deleteCourseById(id);
+            return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
+        } catch (EmptyResultDataAccessException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
+
     }
 }

src/main/java/com/school/project/controller/DepartmentController.java

 package com.school.project.controller;
 
+import com.school.project.dto.CourseDTO;
 import com.school.project.dto.DepartmentDTO;
 import com.school.project.service.implementation.DepartmentServiceImp;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import java.sql.SQLIntegrityConstraintViolationException;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Optional;
 
 @RestController
 public class DepartmentController {
-    @Autowired(required=true)
+    @Autowired(required = true)
     public DepartmentServiceImp departmentServiceImp;
 
-    @GetMapping("department")
+    @GetMapping("departments")
     public ResponseEntity<List<DepartmentDTO>> readAllDepartments() {
         List<DepartmentDTO> departmentDTO = departmentServiceImp.readDepartment();
 
-        if(departmentDTO.isEmpty()){
+        if (departmentDTO.isEmpty()) {
             return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
-        }
-        else {
+        } else {
             return ResponseEntity.of(Optional.of(departmentDTO));
         }
     }
 
     @GetMapping("departmentId/{id}")
-    public ResponseEntity<DepartmentDTO> readDepartmentById(@PathVariable("id") Long id){
+    public ResponseEntity<DepartmentDTO> readDepartmentById(@PathVariable("id") Long id) {
         try {
-                DepartmentDTO departmentDTO=departmentServiceImp.readDepartmentById(id);
+            DepartmentDTO departmentDTO = departmentServiceImp.readDepartmentById(id);
 
-                return ResponseEntity.of(Optional.of(departmentDTO));
+            return ResponseEntity.of(Optional.of(departmentDTO));
 
-        }catch (NoSuchElementException e){
+        } catch (NoSuchElementException e) {
 
             return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
         }
@@ -43,54 +45,49 @@ public class DepartmentController {
     }
 
     @GetMapping("departmentName/{name}")
-    public ResponseEntity<DepartmentDTO> findDepartmentByName(@PathVariable("name") String name){
-        DepartmentDTO departmentDTO=departmentServiceImp.findDepartmentByName(name);
+    public ResponseEntity<DepartmentDTO> findDepartmentByName(@PathVariable("name") String name) {
+        DepartmentDTO departmentDTO = departmentServiceImp.findDepartmentByName(name);
 
-        if(departmentDTO == null){
+        if (departmentDTO == null) {
             return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
-        }else {
+        } else {
             return ResponseEntity.of(Optional.of(departmentDTO));
         }
     }
 
-    @PostMapping("departmentSave")
-    public ResponseEntity<DepartmentDTO> saveDepartment(@RequestBody DepartmentDTO department){
-                DepartmentDTO departmentDTO = departmentServiceImp.saveDepartment(department);
-
-                if(departmentDTO == null){
-                    return ResponseEntity.status(HttpStatus.NOT_ACCEPTABLE).build();
-                }
-                else {
-                    return ResponseEntity.status(HttpStatus.OK).body(departmentDTO);
-                }
-    }
+    @PostMapping("departments")
+    public ResponseEntity<DepartmentDTO> saveDepartment(@RequestBody DepartmentDTO department) {
 
-    @PutMapping("department/{id}")
-    public ResponseEntity<DepartmentDTO> updateDepartmentById(@RequestBody DepartmentDTO department, @PathVariable("id") Long id){
-        DepartmentDTO checkDepartment = departmentServiceImp.readDepartmentById(id);
+        try {
+            DepartmentDTO departmentDTO = departmentServiceImp.saveDepartment(department);
 
-        if(checkDepartment == null){
-            return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
-        }
-        else {
-            DepartmentDTO departmentDTO = departmentServiceImp.updateDepartment(department,id);
+            return ResponseEntity.status(HttpStatus.OK).body(departmentDTO);
 
-            return ResponseEntity.of(Optional.of(departmentDTO));
-        }
-    }
+        } catch (Exception exception) {
 
-    @DeleteMapping("department/{id}")
-    public ResponseEntity<Object> deleteDepartmentById(@PathVariable("id") Long id){
-        departmentServiceImp.deleteDepartmentById(id);
+            return ResponseEntity.status(HttpStatus.BAD_REQUEST).build();
 
-        DepartmentDTO departmentDTO = departmentServiceImp.readDepartmentById(id);
+        }
 
-        if(departmentDTO == null){
-            return ResponseEntity.status(HttpStatus.OK).build();
-        }else {
+    }
 
-            return  ResponseEntity.of(Optional.of("Department Already Not Exist"));
+    @PutMapping("departments/{id}")
+    public ResponseEntity<DepartmentDTO> updateDepartmentById(@RequestBody DepartmentDTO department, @PathVariable("id") Long id) {
+        try {
+            DepartmentDTO updateDepartment = departmentServiceImp.updateDepartment(department, id);
+            return ResponseEntity.status(HttpStatus.OK).body(updateDepartment);
+        } catch (NoSuchElementException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
         }
+    }
 
+    @DeleteMapping("departments/{id}")
+    public ResponseEntity<Object> deleteDepartmentById(@PathVariable("id") Long id) {
+        try {
+            departmentServiceImp.deleteDepartmentById(id);
+            return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
+        } catch (EmptyResultDataAccessException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
     }
 }

src/main/java/com/school/project/controller/StudentController.java

 package com.school.project.controller;
 
+import com.school.project.dto.DepartmentDTO;
+import com.school.project.dto.StudentDTO;
 import com.school.project.model.Student;
+import com.school.project.service.implementation.StudentServiceImp;
 import com.school.project.service.interfaces.StudentService;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.Optional;
 
 @RestController
 public class StudentController {
-    @Autowired(required=true)
-    public StudentService studentService;
+    @Autowired(required = true)
+    public StudentServiceImp studentServiceImp;
 
-    @PostMapping("/student")
-    public Student saveStudent(@RequestBody Student student){
-        return studentService.saveStudent(student);
+    @PostMapping("/students")
+    public ResponseEntity<StudentDTO> saveStudent(@RequestBody StudentDTO studentDTO) {
+
+        StudentDTO student = studentServiceImp.saveStudent(studentDTO);
+
+        if (student == null) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        } else {
+            return ResponseEntity.status(HttpStatus.OK).body(student);
+        }
     }
 
     @GetMapping("/students")
-    public ResponseEntity<List<Student>> readAllStudents(){
-        List<Student> students=studentService.readAllStudents();
-        if(students.size()<=0){
+    public ResponseEntity<List<StudentDTO>> readAllStudents() {
+        List<StudentDTO> studentsDTO = studentServiceImp.readAllStudents();
+
+        if (studentsDTO.size() <= 0) {
             return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
+        } else {
+            return ResponseEntity.status(HttpStatus.OK).body(studentsDTO);
         }
-
-        return ResponseEntity.of(Optional.of(students));
-
     }
 
-    @GetMapping("student/{id}")
-    public Optional<Student> readStudentById(@PathVariable("id") Long id){
-       return studentService.readStudentById(id);
+    @GetMapping("students/{id}")
+    public ResponseEntity<StudentDTO> readStudentById(@PathVariable("id") Long id) {
+
+        try {
+            StudentDTO dto = studentServiceImp.readStudentById(id);
+            return ResponseEntity.status(HttpStatus.OK).body(dto);
+        } catch (NoSuchElementException e) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
+        }
 
     }
 
-    @PutMapping("student/{id}")
-    public Student updateStudentById(@RequestBody Student student,@PathVariable("id") Long id){
-        return studentService.updateStudentById(student,id);
+    @PutMapping("students/{id}")
+    public ResponseEntity<StudentDTO> updateStudentById(@RequestBody StudentDTO studentDTO, @PathVariable("id") Long id) {
+        try {
+            StudentDTO updateStudent = studentServiceImp.updateStudentById(studentDTO, id);
+            return ResponseEntity.status(HttpStatus.OK).body(updateStudent);
+        } catch (NoSuchElementException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
+
     }
 
-    @DeleteMapping("student/{id}")
-    public void deleteStudentById(@PathVariable("id") Long id){
-        studentService.deleteStudentById(id);
+    @DeleteMapping("students/{id}")
+    public ResponseEntity deleteStudentById(@PathVariable("id") Long id) {
+        try {
+            studentServiceImp.deleteStudentById(id);
+            return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
+        } catch (EmptyResultDataAccessException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
     }
-}
+}
\ No newline at end of file

src/main/java/com/school/project/controller/TeacherController.java

 package com.school.project.controller;
 
+import com.school.project.dto.DepartmentDTO;
+import com.school.project.dto.TeacherDTO;
 import com.school.project.model.Teacher;
 import com.school.project.service.implementation.TeacherServiceImp;
 import com.school.project.service.interfaces.TeacherService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.ComponentScan;
+import org.springframework.dao.EmptyResultDataAccessException;
+import org.springframework.http.HttpRange;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
+import java.util.NoSuchElementException;
 import java.util.Optional;
 
 @RestController
@@ -15,31 +22,60 @@ import java.util.Optional;
 public class TeacherController {
 
     @Autowired(required = true)
-    public TeacherServiceImp teacherService;
+    public TeacherServiceImp teacherServiceImp;
 
-    @PostMapping("/teacher")
-    public Teacher saveTeacher(@RequestBody Teacher teacher){
-        return teacherService.saveTeacher(teacher);
+    @PostMapping("/saveTeachers")
+    public ResponseEntity<TeacherDTO> saveTeacher(@RequestBody TeacherDTO teacherDTO) {
+        TeacherDTO dto = teacherServiceImp.saveTeacher(teacherDTO);
+
+        if (dto == null) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        } else {
+            return ResponseEntity.status(HttpStatus.OK).body(dto);
+        }
     }
 
     @GetMapping("/teachers")
-    public List<Teacher> readAllTeachers(){
-        return (List<Teacher>) teacherService.readAllTeachers();
+    public ResponseEntity<List<TeacherDTO>> readAllTeachers() {
+        List<TeacherDTO> teacherDTOS = teacherServiceImp.readAllTeachers();
+
+        if (teacherDTOS.size() <= 0) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        } else {
+            return ResponseEntity.status(HttpStatus.OK).body(teacherDTOS);
+        }
     }
 
-    @GetMapping("teacher/{id}")
-    public Optional<Teacher> readTeacherById(@PathVariable("id") Long id){
-        return teacherService.readTeacherById(id);
+    @GetMapping("teachers/{id}")
+    public ResponseEntity<TeacherDTO> readTeacherById(@PathVariable("id") Long id) {
+
+        try {
+            TeacherDTO teacherDTO = teacherServiceImp.readTeacherById(id);
+            return ResponseEntity.status(HttpStatus.OK).body(teacherDTO);
+        } catch (NoSuchElementException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
+
     }
 
-    @PutMapping("teacher/{id}")
-    public Teacher updateTeacherById(@RequestBody Teacher teacher,@PathVariable("id") Long id){
-        return teacherService.updateTeacher(teacher,id);
+    @PutMapping("teachers/{id}")
+    public ResponseEntity<TeacherDTO> updateTeacherById(@RequestBody TeacherDTO teacherDTO, @PathVariable("id") Long id) {
+        try {
+            TeacherDTO updateTeacher = teacherServiceImp.updateTeacher(teacherDTO, id);
+            return ResponseEntity.status(HttpStatus.OK).body(updateTeacher);
+        } catch (NoSuchElementException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
     }
 
-    @DeleteMapping("teacher/{id}")
-    public void deleteTeacherById(@PathVariable("id") Long id){
-        teacherService.deleteTeacherById(id);
+    @DeleteMapping("teachers/{id}")
+    public ResponseEntity deleteTeacherById(@PathVariable("id") Long id) {
+        try {
+            teacherServiceImp.deleteTeacherById(id);
+            return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
+        } catch (EmptyResultDataAccessException e) {
+            return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).build();
+        }
     }
 
 }

src/main/java/com/school/project/controller/UserController.java

@@ -19,11 +19,11 @@ public class UserController {
     UserMapper userMapper;
 
     @PostMapping("/saveuser")
-    public String saveUser(@ModelAttribute UserDTO userDTO){
+    public String saveUser(@ModelAttribute UserDTO userDTO) {
 
         Integer id = userService.saveUser(userMapper.userDtoToUser(userDTO));
 
-        String message = "User '"+id+"' saved successfully !";
+        String message = "User '" + id + "' saved successfully !";
 
         return message;
     }

src/main/java/com/school/project/dto/CourseDTO.java

@@ -9,12 +9,12 @@ import java.util.List;
 @Data
 public class CourseDTO {
 
-     private Long id;
+    private Long id;
 
-     private String title;
+    private String title;
 
-     List<Student> studentList;
+    List<Student> studentList;
 
-     private Teacher teacher;
+    private List<Teacher> teacherList;
 
 }

src/main/java/com/school/project/dto/DepartmentDTO.java

 package com.school.project.dto;
 
+import com.school.project.model.Teacher;
 import lombok.Data;
 
+import java.util.List;
+
 @Data
 public class DepartmentDTO {
 
     private Long id;
+
     private String name;
+
 }

src/main/java/com/school/project/dto/TeacherDTO.java

@@ -15,7 +15,7 @@ public class TeacherDTO {
 
     private String degree;
 
-    private Course course;
+    private List<Course> courseList;
 
     private Department department;
 }

src/main/java/com/school/project/mapper/CourseMapper.java

@@ -6,11 +6,16 @@ import com.school.project.model.Course;
 import org.mapstruct.Mapper;
 import org.mapstruct.factory.Mappers;
 
+import java.util.List;
+
 @Mapper(componentModel = "spring")
 public interface CourseMapper {
 
     CourseMapper INSTANCE = Mappers.getMapper(CourseMapper.class);
+
     CourseDTO courseModelToDTO(Course course);
+
     Course courseDTOToModel(CourseDTO courseDTO);
 
+    List<CourseDTO> courseModelToDTO(List<Course> all);
 }

src/main/java/com/school/project/mapper/DepartmentMapper.java

@@ -14,7 +14,9 @@ public interface DepartmentMapper {
     DepartmentMapper INSTANCE = Mappers.getMapper(DepartmentMapper.class);
 
     DepartmentDTO departmentModelToDTO(Department department);
+
     Department departmentDTOToModel(DepartmentDTO saveDepartment);
+
     List<DepartmentDTO> departmentListModelToDTO(List<Department> all);
 
     /*@Mappings({

src/main/java/com/school/project/mapper/StudentMapper.java

@@ -5,10 +5,17 @@ import com.school.project.model.Student;
 import org.mapstruct.Mapper;
 import org.mapstruct.factory.Mappers;
 
+import java.util.List;
+import java.util.Optional;
+
 @Mapper(componentModel = "spring")
 public interface StudentMapper {
 
     StudentMapper INSTANCE = Mappers.getMapper(StudentMapper.class);
+
     StudentDTO studentModelToDTO(Student student);
+
     Student studentDTOToModel(StudentDTO studentDTO);
+
+    List<StudentDTO> studentModelToDTO(List<Student> all);
 }

src/main/java/com/school/project/mapper/TeacherMapper.java

@@ -5,6 +5,8 @@ import com.school.project.model.Teacher;
 import org.mapstruct.Mapper;
 import org.mapstruct.factory.Mappers;
 
+import java.util.List;
+
 @Mapper(componentModel = "spring")
 public interface TeacherMapper {
 
@@ -13,4 +15,6 @@ public interface TeacherMapper {
     TeacherDTO teacherModelToDTo(Teacher teacher);
 
     Teacher teacherDTOToModel(TeacherDTO teacherDTO);
+
+    List<TeacherDTO> teacherModelToDTo(List<Teacher> all);
 }

src/main/java/com/school/project/model/Course.java

 package com.school.project.model;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import lombok.Data;
+
 import javax.persistence.*;
 import java.util.List;
 
@@ -12,14 +14,16 @@ public class Course {
     @Id
     @GeneratedValue(strategy = GenerationType.AUTO)
     private Long id;
-    @Column(name = "title")
+
+    @Column(name = "title", unique = true)
     private String title;
 
     @ManyToMany(fetch = FetchType.LAZY, mappedBy = "courseLists")
-    List<Student> studentList;
-
-    @OneToOne(mappedBy = "course",orphanRemoval = true )
-    private Teacher teacher;
+    @JsonIgnore
+    private List<Student> studentList;
 
+    @ManyToMany(fetch = FetchType.LAZY, mappedBy = "courseList")
+    @JsonIgnore
+    private List<Teacher> teacherList;
 
 }

src/main/java/com/school/project/model/Department.java

@@ -3,6 +3,7 @@ package com.school.project.model;
 import lombok.Data;
 
 import javax.persistence.*;
+import java.util.List;
 
 @Data
 @Entity()
@@ -13,7 +14,7 @@ public class Department {
     @GeneratedValue(strategy = GenerationType.SEQUENCE)
     private Long id;
 
-    @Column(name = "name",unique = true)
+    @Column(name = "name", unique = true)
     private String name;
 
 }

src/main/java/com/school/project/model/Student.java

 package com.school.project.model;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import lombok.Data;
+
 import javax.persistence.*;
 import java.util.List;
 
@@ -14,17 +16,19 @@ public class Student {
     @GeneratedValue(strategy = GenerationType.SEQUENCE)
     private Long id;
 
-    @Column(name="name")
+    @Column(name = "name")
     private String name;
 
     @Column(name = "age")
     private Long age;
-    @ManyToMany(fetch = FetchType.LAZY,cascade = { CascadeType.MERGE })
+
+    @ManyToMany(fetch = FetchType.LAZY, cascade = {CascadeType.MERGE})
     @JoinTable(
             name = "studentsCourses",
-            joinColumns = { @JoinColumn(name = "student_id") },
-            inverseJoinColumns = { @JoinColumn(name = "course_id") }
+            joinColumns = {@JoinColumn(name = "student_id")},
+            inverseJoinColumns = {@JoinColumn(name = "course_id")}
     )
+    @JsonIgnore
     private List<Course> courseLists;
 
 }

src/main/java/com/school/project/model/Teacher.java

 package com.school.project.model;
 
 import lombok.Data;
+import org.codehaus.jackson.annotate.JsonIgnore;
+
 import javax.persistence.*;
 import java.util.List;
 
 @Data
 @Entity
-@Table(name="Teacher")
+@Table(name = "Teacher")
 public class Teacher {
 
     @Id
@@ -19,12 +21,18 @@ public class Teacher {
     @Column(name = "degree")
     private String degree;
 
-    @OneToOne
-    @JoinColumn(name = "course_id")
-    private Course course;
-
-    @ManyToOne(fetch = FetchType.EAGER, cascade = CascadeType.MERGE)
-    @JoinColumn(name = "department_id",unique = true)
+    @ManyToMany(fetch = FetchType.EAGER, cascade = {CascadeType.MERGE})
+    @JoinTable(
+            name = "teachersCourses",
+            joinColumns = {@JoinColumn(name = "teacher_id")},
+            inverseJoinColumns = {@JoinColumn(name = "course_id")}
+    )
+    @JsonIgnore
+    private List<Course> courseList;
+
+    @ManyToOne(fetch = FetchType.EAGER)
+    @JoinColumn(name = "department_id")
+    @JsonIgnore
     private Department department;
 
 }

src/main/java/com/school/project/model/User.java

@@ -26,7 +26,7 @@ public class User {
     @Column(name = "user_email")
     private String email;
 
-    @ElementCollection(fetch= FetchType.EAGER)
+    @ElementCollection(fetch = FetchType.EAGER)
     @CollectionTable(
             name = "roles",
             joinColumns = @JoinColumn(name = "user_id")

src/main/java/com/school/project/repository/CourseRepository.java

@@ -5,5 +5,5 @@ import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
 @Repository
-public interface CourseRepository extends JpaRepository<Course,Long> {
+public interface CourseRepository extends JpaRepository<Course, Long> {
 }

src/main/java/com/school/project/repository/DepartmentRepository.java

@@ -5,6 +5,6 @@ import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
 @Repository
-public interface DepartmentRepository extends JpaRepository<Department,Long>{
+public interface DepartmentRepository extends JpaRepository<Department, Long> {
     public Department findByName(String departmentName);
 }

src/main/java/com/school/project/repository/StudentRepository.java

@@ -5,6 +5,6 @@ import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
 @Repository
-public interface StudentRepository extends JpaRepository<Student,Long> {
+public interface StudentRepository extends JpaRepository<Student, Long> {
 
 }

src/main/java/com/school/project/repository/TeacherRepository.java

@@ -5,5 +5,5 @@ import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
 @Repository
-public interface TeacherRepository extends JpaRepository<Teacher,Long> {
+public interface TeacherRepository extends JpaRepository<Teacher, Long> {
 }

src/main/java/com/school/project/repository/UserRepository.java

@@ -7,7 +7,7 @@ import org.springframework.stereotype.Repository;
 import java.util.Optional;
 
 @Repository
-public interface UserRepository extends JpaRepository<User,Long> {
+public interface UserRepository extends JpaRepository<User, Long> {
 
     Optional<User> findUserByEmail(String email);
 }

src/main/java/com/school/project/security/basic/OAuth2ServerConfiguration.java → src/main/java/com/school/project/security/OAuth2ServerConfiguration.java

-package com.school.project.security.basic;
+package com.school.project.security;
 
 
 import org.springframework.beans.factory.annotation.Autowired;
@@ -26,8 +26,8 @@ public class OAuth2ServerConfiguration {
     private static InMemoryTokenStore tokenStore = new InMemoryTokenStore();
 
     @Bean
-    public PasswordEncoder passwordEncoder(){
-        return new  BCryptPasswordEncoder();
+    public PasswordEncoder passwordEncoder() {
+        return new BCryptPasswordEncoder();
     }
 
     @Configuration
@@ -49,6 +49,7 @@ public class OAuth2ServerConfiguration {
                     .and()
                     .authorizeRequests()
                     .antMatchers("/department").fullyAuthenticated()
+                    .antMatchers("/saveuser").permitAll()
                     .antMatchers("/home").authenticated();
         }
     }

src/main/java/com/school/project/security/basic/SecurityConfig.java → src/main/java/com/school/project/security/SecurityConfig.java

-package com.school.project.security.basic;
+package com.school.project.security;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
@@ -31,6 +31,7 @@ public class SecurityConfig extends WebSecurityConfigurerAdapter {
         http
                 .requestMatcher(new BasicRequestMatcher())
                 .authorizeRequests()
+                .antMatchers("/saveuser").permitAll()
                 .antMatchers("/oauth/token").authenticated()
                 .and()
                 .httpBasic()

src/main/java/com/school/project/service/implementation/CourseServiceImp.java

 package com.school.project.service.implementation;
 
+import com.school.project.dto.CourseDTO;
+import com.school.project.mapper.CourseMapper;
 import com.school.project.model.Course;
 import com.school.project.repository.CourseRepository;
 import com.school.project.service.interfaces.CourseService;
@@ -16,25 +18,44 @@ public class CourseServiceImp implements CourseService {
     @Autowired(required = true)
     public CourseRepository courseRepository;
 
+    @Autowired
+    public CourseMapper courseMapper;
+
     @Override
-    public Course saveCourse(Course course) {
-        return courseRepository.save(course);
+    public CourseDTO saveCourse(CourseDTO courseDTO) {
+        return courseMapper.courseModelToDTO(
+                courseRepository.save(
+                        courseMapper.courseDTOToModel(courseDTO)));
     }
 
     @Transactional
     @Override
-    public List<Course> readAllCourse() {
-        return courseRepository.findAll();
+    public List<CourseDTO> readAllCourse() {
+        return courseMapper.courseModelToDTO(courseRepository.findAll());
     }
 
     @Override
-    public Optional<Course> readCourseById(Long id) {
-        return courseRepository.findById(id);
+    public CourseDTO readCourseById(Long id) {
+        return courseMapper.courseModelToDTO(courseRepository.findById(id).get());
     }
 
     @Override
-    public Course updateCourseById(Course course, Long id) {
-            return course;
+    public CourseDTO updateCourseById(CourseDTO courseDTO, Long id) {
+        CourseDTO dto = readCourseById(id);
+
+        if (courseDTO.getTitle() != null) {
+            dto.setTitle(courseDTO.getTitle());
+        }
+        if (courseDTO.getTeacherList() != null) {
+            dto.setTeacherList(courseDTO.getTeacherList());
+        }
+        if (courseDTO.getStudentList() != null) {
+            dto.setStudentList(courseDTO.getStudentList());
+        }
+
+        return courseMapper.courseModelToDTO(
+                courseRepository.save(
+                        courseMapper.courseDTOToModel(dto)));
     }
 
     @Override

src/main/java/com/school/project/service/implementation/DepartmentServiceImp.java

@@ -11,7 +11,7 @@ import java.util.List;
 
 @Service
 public class DepartmentServiceImp implements DepartmentService {
-    @Autowired(required=true)
+    @Autowired(required = true)
     private DepartmentRepository departmentRepository;
     @Autowired(required = true)
     private DepartmentMapper departmentMapper;
@@ -28,9 +28,10 @@ public class DepartmentServiceImp implements DepartmentService {
         return departmentMapper.departmentListModelToDTO(departmentRepository.findAll());
 
     }
+
     @Override
     public DepartmentDTO readDepartmentById(Long departmentId) {
-            return departmentMapper.departmentModelToDTO(departmentRepository.findById(departmentId).get());
+        return departmentMapper.departmentModelToDTO(departmentRepository.findById(departmentId).get());
     }
 
     @Override
@@ -43,10 +44,12 @@ public class DepartmentServiceImp implements DepartmentService {
 
         return departmentMapper.departmentModelToDTO(departmentRepository.findById(departmentId).get());
     }
+
     @Override
     public void deleteDepartmentById(Long departmentId) {
-            departmentRepository.deleteById(departmentId);
+        departmentRepository.deleteById(departmentId);
     }
+
     @Override
     public DepartmentDTO findDepartmentByName(String departmentName) {
 

src/main/java/com/school/project/service/implementation/StudentServiceImp.java

 package com.school.project.service.implementation;
 
-import com.school.project.model.Student;
+import com.school.project.dto.StudentDTO;
+import com.school.project.mapper.StudentMapper;
 import com.school.project.repository.StudentRepository;
 import com.school.project.service.interfaces.StudentService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
-import java.util.Optional;
 
 @Service
 public class StudentServiceImp implements StudentService {
-    @Autowired(required=true)
+    @Autowired(required = true)
     public StudentRepository studentRepository;
 
+    @Autowired
+    public StudentMapper studentMapper;
+
     @Override
-    public Student saveStudent(Student student) {
-        return studentRepository.save(student);
+    public StudentDTO saveStudent(StudentDTO studentDTO) {
+        return studentMapper.studentModelToDTO(
+                studentRepository.save(
+                        studentMapper.studentDTOToModel(studentDTO)));
     }
 
     @Override
-    public List<Student> readAllStudents() {
-        return studentRepository.findAll();
+    public List<StudentDTO> readAllStudents() {
+        return studentMapper.studentModelToDTO(studentRepository.findAll());
     }
 
     @Override
-    public Optional<Student> readStudentById(Long id) {
-        return studentRepository.findById(id);
+    public StudentDTO readStudentById(Long id) {
+        return (studentMapper.studentModelToDTO(studentRepository.findById(id).get()));
     }
 
     @Override
-    public Student updateStudentById(Student student, Long id) {
-        return student;
+    public StudentDTO updateStudentById(StudentDTO studentDTO, Long id) {
+        StudentDTO dto = studentMapper.studentModelToDTO(studentRepository.findById(id).get());
+
+        if (studentDTO.getName() != null) {
+            dto.setName(studentDTO.getName());
+        }
+        if (studentDTO.getAge() != null) {
+            dto.setAge(studentDTO.getAge());
+        }
+        if (studentDTO.getCourseLists() != null) {
+            dto.setCourseLists(studentDTO.getCourseLists());
+        }
+
+        return studentMapper.studentModelToDTO(
+                studentRepository.save(
+                        studentMapper.studentDTOToModel(dto)));
     }
 
     @Override

src/main/java/com/school/project/service/implementation/TeacherServiceImp.java

 package com.school.project.service.implementation;
 
+import com.school.project.dto.TeacherDTO;
+import com.school.project.mapper.TeacherMapper;
 import com.school.project.model.Teacher;
 import com.school.project.repository.TeacherRepository;
 import com.school.project.service.interfaces.TeacherService;
@@ -13,26 +15,46 @@ import java.util.Optional;
 public class TeacherServiceImp implements TeacherService {
 
     @Autowired(required = true)
-    public TeacherRepository teacherRepository;
+    private TeacherRepository teacherRepository;
+
+    @Autowired
+    private TeacherMapper teacherMapper;
 
     @Override
-    public Teacher saveTeacher(Teacher teacher) {
-        return teacherRepository.save(teacher);
+    public TeacherDTO saveTeacher(TeacherDTO teacherDTO) {
+        return teacherMapper.teacherModelToDTo(
+                teacherRepository.save(
+                        teacherMapper.teacherDTOToModel(teacherDTO)));
     }
 
     @Override
-    public List<Teacher> readAllTeachers() {
-        return teacherRepository.findAll();
+    public List<TeacherDTO> readAllTeachers() {
+        return teacherMapper.teacherModelToDTo(teacherRepository.findAll());
     }
 
     @Override
-    public Optional<Teacher> readTeacherById(Long id) {
-        return teacherRepository.findById(id);
+    public TeacherDTO readTeacherById(Long id) {
+        return teacherMapper.teacherModelToDTo(teacherRepository.findById(id).get());
     }
 
     @Override
-    public Teacher updateTeacher(Teacher teacher, Long id) {
-        return null;
+    public TeacherDTO updateTeacher(TeacherDTO teacherDTO, Long id) {
+        TeacherDTO dto = readTeacherById(id);
+
+        if (teacherDTO.getName() != null) {
+            dto.setName(teacherDTO.getName());
+        }
+        if (teacherDTO.getDegree() != null) {
+            dto.setDegree(teacherDTO.getDegree());
+        }
+        if (teacherDTO.getCourseList() != null) {
+            dto.setCourseList(teacherDTO.getCourseList());
+        }
+        if (teacherDTO.getDepartment() != null) {
+            dto.setDepartment(teacherDTO.getDepartment());
+        }
+
+        return saveTeacher(dto);
     }
 
     @Override

src/main/java/com/school/project/service/implementation/UserServiceImpl.java

@@ -45,11 +45,11 @@ public class UserServiceImpl implements UserService, UserDetailsService {
 
         Optional<User> userEmail = userRepository.findUserByEmail(email);
 
-        org.springframework.security.core.userdetails.User springUser=null;
+        org.springframework.security.core.userdetails.User springUser = null;
 
-        if(userEmail.isEmpty()){
-            throw  new UsernameNotFoundException("User With Email=" + email + "Not Founnd");
-        }else{
+        if (userEmail.isEmpty()) {
+            throw new UsernameNotFoundException("User With Email=" + email + "Not Founnd");
+        } else {
 
             User user = userEmail.get();
 
@@ -57,14 +57,14 @@ public class UserServiceImpl implements UserService, UserDetailsService {
 
             Set<GrantedAuthority> userAuthorities = new HashSet<>();
 
-            for (String userRole:userRoles){
+            for (String userRole : userRoles) {
                 userAuthorities.add(new SimpleGrantedAuthority(userRole));
             }
 
             springUser = new org.springframework.security.core.userdetails.User(
                     email,
                     user.getPassword(),
-                    userAuthorities );
+                    userAuthorities);
         }
 
         return springUser;

src/main/java/com/school/project/service/interfaces/CourseService.java

 package com.school.project.service.interfaces;
 
+import com.school.project.dto.CourseDTO;
 import com.school.project.model.Course;
 
 import java.util.List;
@@ -7,13 +8,13 @@ import java.util.Optional;
 
 public interface CourseService {
 
-    public Course saveCourse(Course course);
+    public CourseDTO saveCourse(CourseDTO courseDTO);
 
-    public List<Course> readAllCourse();
+    public List<CourseDTO> readAllCourse();
 
-    public Optional<Course> readCourseById(Long id);
+    public CourseDTO readCourseById(Long id);
 
-    public Course updateCourseById(Course course,Long id);
+    public CourseDTO updateCourseById(CourseDTO courseDTO, Long id);
 
     public void deleteCourseById(Long id);
 }

src/main/java/com/school/project/service/interfaces/DepartmentService.java

@@ -6,10 +6,15 @@ import java.util.List;
 
 public interface DepartmentService {
     public DepartmentDTO saveDepartment(DepartmentDTO departmentDTO);
+
     public List<DepartmentDTO> readDepartment();
+
     public DepartmentDTO readDepartmentById(Long id);
-    public DepartmentDTO updateDepartment(DepartmentDTO departmentDTO,Long id);
+
+    public DepartmentDTO updateDepartment(DepartmentDTO departmentDTO, Long id);
+
     public void deleteDepartmentById(Long id);
+
     public DepartmentDTO findDepartmentByName(String departmentName);
 
 }

src/main/java/com/school/project/service/interfaces/StudentService.java

 package com.school.project.service.interfaces;
 
+import com.school.project.dto.StudentDTO;
 import com.school.project.model.Student;
 
 import java.util.List;
-import java.util.Optional;
 
 public interface StudentService {
 
-    public Student saveStudent(Student student);
+    public StudentDTO saveStudent(StudentDTO studentDTO);
 
-    public List<Student> readAllStudents();
+    public List<StudentDTO> readAllStudents();
 
-    public Optional<Student> readStudentById(Long id);
+    public StudentDTO readStudentById(Long id);
 
-    public Student updateStudentById(Student student,Long id);
+    public StudentDTO updateStudentById(StudentDTO studentDTO, Long id);
 
     public void deleteStudentById(Long id);
 

src/main/java/com/school/project/service/interfaces/TeacherService.java

 package com.school.project.service.interfaces;
 
+import com.school.project.dto.TeacherDTO;
 import com.school.project.model.Teacher;
 import org.springframework.stereotype.Service;
 
@@ -9,13 +10,13 @@ import java.util.Optional;
 @Service
 public interface TeacherService {
 
-    public Teacher saveTeacher(Teacher teacher);
+    public TeacherDTO saveTeacher(TeacherDTO teacherDTO);
 
-    public List<Teacher> readAllTeachers();
+    public List<TeacherDTO> readAllTeachers();
 
-    public Optional<Teacher> readTeacherById(Long id);
+    public TeacherDTO readTeacherById(Long id);
 
-    public Teacher updateTeacher(Teacher teacher,Long id);
+    public TeacherDTO updateTeacher(TeacherDTO teacherDTO, Long id);
 
     public void deleteTeacherById(Long id);
 

src/main/resources/application.properties

+#
+#spring.jpa.hibernate.ddl-auto=update
+#spring.datasource.url=jdbc:mysql://localhost:3306/schoolDataBase
+#spring.datasource.username=root
+#spring.datasource.password=charlie123
 
 spring.jpa.hibernate.ddl-auto=update
-spring.datasource.url=jdbc:mysql://localhost:3306/schoolDataBase
+spring.datasource.url=jdbc:mysql://localhost:3306/schooldataBase
 spring.datasource.username=root
-spring.datasource.password=charlie123
+spring.datasource.password=root
 
 spring.security.user.name= sulemantalpur6@gmail.com
 spring.security.user.password=charlie