Cài đặt môi trường, chuẩn bị ứng dụng Springboot

cd $HOME
mkdir .kube
cd .kube
microk8s config > config

kubectl config use-context microk8s

# Tạo mới học sinh:
curl --location --request POST 'localhost:8080/api/students' \
--header 'Content-Type: application/json' \
--data-raw '{
    "fullName": "NGUYEN BA THANH",
    "dateOfBirth": "29/04/1998",
    "hometown": "HA DONG, HA NOI",
    "gender": "MALE"
}'

# Danh sách học sinh:
curl --location --request GET 'localhost:8080/api/students'

# Tạo mới khóa học:
curl --location --request POST 'localhost:8081/api/courses/v1/createCourse' \
--header 'Content-Type: application/json' \
--data-raw '{
    "name": "HOC LAM GIAU",
    "desc": "NEU MUON CO 100 ti THI PHAI THAM GIA NGAY :D",
    "author": "VNTechies"
}'

# Tham gia khóa học:
curl --location --request POST 'localhost:8081/api/courses/v1/joinCourse' \
--header 'Content-Type: application/json' \
--data-raw '{
    "courseId": "1",
    "studentId": "1"
}'

# Lấy thông tin chi tiết khóa học:
curl --location --request GET 'localhost:8081/api/courses/v1/getCourseDetailBy?courseId=1'

server:
  port: ${SERVER_PORT:8081}

# Cấu hình thông tin database (MySQL) gồm: tên database, username và password của user MySQL.
spring:
  datasource:
    driverClassName: com.mysql.jdbc.Driver
    url: ${MYSQL_URL:jdbc:mysql://localhost:3306/students}
    username: ${MYSQL_USERNAME:students}
    password: ${MYSQL_PASSWORD:VNTechies2023}
  jpa:
    hibernate.ddl-auto: update
    generate-ddl: true
    show-sql: true

@Data
@Entity
@AllArgsConstructor
@NoArgsConstructor
@Table(name = "students")
public class Student {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "fullName")
    private String fullName;

    @Column(name = "dob")
    private String dateOfBirth;

    @Column(name = "hometown")
    private String hometown;

    @Column(name = "gender")
    @Enumerated(EnumType.STRING)
    private Gender gender;

    public static Student createFrom(CreateStudentRequest request) {
        Student student = new Student();
        student.setFullName(request.getFullName());
        student.setDateOfBirth(request.getDateOfBirth());
        student.setHometown(request.getHometown());
        student.setGender(request.getGender());
        return student;
    }
}

@RestController
@RequestMapping(value = "/api/students")
public class StudentControllers {

    private final IStudentService iStudentService;

    public StudentControllers(IStudentService iStudentService) {
        this.iStudentService = iStudentService;
    }

    @PostMapping
    public ResponseEntity<StudentDTO> createStudent(@RequestBody CreateStudentRequest request) {
        return new ResponseEntity<>(iStudentService.createStudent(request), HttpStatus.CREATED);
    }

    @GetMapping
    public ResponseEntity<List<StudentDTO>> getAllStudents() {
        return new ResponseEntity<>(iStudentService.getAll(), HttpStatus.OK);
    }
}

@Service
public class StudentServiceImpl implements IStudentService {

    private static final ObjectMapper objectMapper = new ObjectMapper();
    private final IStudentRepository iStudentRepository;

    public StudentServiceImpl(IStudentRepository iStudentRepository) {
        this.iStudentRepository = iStudentRepository;
    }

    @Override
    public StudentDTO createStudent(CreateStudentRequest request) {
        Student student = iStudentRepository.save(Student.createFrom(request));
        return objectMapper.convertValue(student, StudentDTO.class);
    }

    @Override
    public List<StudentDTO> getAll() {
        List<Student> students = iStudentRepository.findAll();
        List<StudentDTO> studentRespList = new ArrayList<>();
        for (Student student : students) {
            StudentDTO studentResp = objectMapper.convertValue(student, StudentDTO.class);
            studentRespList.add(studentResp);
        }
        return studentRespList;
    }
}

server:
  port : ${SERVER_PORT:8080}

# Cấu hình thông tin database (MySQL) gồm: tên database, username và password của user MySQL.
spring:
  datasource:
    driverClassName: com.mysql.jdbc.Driver
    url: ${MYSQL_URL:jdbc:mysql://localhost:3306/courses}
    username: ${MYSQL_USERNAME:courses}
    password: ${MYSQL_PASSWORD:VNTechies2023}
  jpa:
    hibernate.ddl-auto: update
    generate-ddl: true
    show-sql: true

# Cấu hình thông tin URI của Students service.
clients:
  services:
    students:
      uri: ${STUDENTS_URI:http://localhost:8081}

@Data
@Entity
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "courses")
public class Courses {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "name")
    private String name;

    @Column(name = "description")
    private String desc;

    @Column(name = "author")
    private String author;
}

@Data
@Entity
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "courses_members")
public class CoursesMembers {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "course_id")
    private Long courseId;

    @Column(name = "member_id")
    private Long memberId;

    public CoursesMembers(Long courseId, Long memberId) {
        this.courseId = courseId;
        this.memberId = memberId;
    }
}

@RestController
@RequestMapping(value = "/api/courses")
public class CoursesControllers {

    private final ICoursesService iCoursesService;

    public CoursesControllers(ICoursesService iCoursesService) {
        this.iCoursesService = iCoursesService;
    }

    @PostMapping(value = "/v1/createCourse")
    public ResponseEntity<BaseResponse<CourseDto>> createCourse(@RequestBody CreateCourseReq req) {
        return new ResponseEntity<>(BaseResponse.buildSuccessResp(iCoursesService.createCourse(req)), HttpStatus.OK);
    }

    @PostMapping(value = "/v1/joinCourse")
    public ResponseEntity<BaseResponse<CourseDto>> joinCourse(@RequestBody JoinCourseReq req) {
        return new ResponseEntity<>(BaseResponse.buildSuccessResp(iCoursesService.joinCourse(req)), HttpStatus.OK);
    }

    @GetMapping(value = "/v1/getCourseDetailBy")
    public ResponseEntity<BaseResponse<CourseDetail>> getCourseDetailBy(@RequestParam(name = "courseId") Long courseId) {
        return new ResponseEntity<>(BaseResponse.buildSuccessResp(iCoursesService.getCourseDetailBy(courseId)), HttpStatus.OK);
    }
}

@Service
@AllArgsConstructor
public class CoursesServiceImpl implements ICoursesService {

    private final ObjectMapper objectMapper;
    private final IStudentClient iStudentClient;
    private final ICoursesRepository iCoursesRepository;
    private final ICoursesMembersRepository iCoursesMembersRepository;

    @Override
    public CourseDto createCourse(CreateCourseReq req) {
        Courses courses = new Courses();
        courses.setName(req.getName());
        courses.setAuthor(req.getAuthor());
        courses.setDesc(req.getDesc());
        Courses coursesDB = iCoursesRepository.save(courses);
        return objectMapper.convertValue(coursesDB, CourseDto.class);
    }

    @Override
    public CourseDetail getCourseDetailBy(Long courseId) {
        CourseDetail courseDetail = new CourseDetail();
        Courses courses = iCoursesRepository.findByID(courseId);
        if (Objects.isNull(courses)) {
            throw new CustomException("Courses not found!");
        }
        List<Long> membersId = new ArrayList<>();
        List<CoursesMembers> membersOfCourse = iCoursesMembersRepository.getAllById(courseId);
        for (CoursesMembers member : membersOfCourse) {
            membersId.add(member.getMemberId());
        }
        if (!membersId.isEmpty()) {
            GetStudentsByIdsResp studentsResp = iStudentClient.getStudentsByIds(new GetStudentsByIdsReq(membersId));
            List<MemberInfo> membersInfo = studentsResp.getStudents().stream()
                    .map(studentDTO -> objectMapper.convertValue(studentDTO, MemberInfo.class))
                    .collect(Collectors.toList());

            courseDetail.setMembers(membersInfo);
        }
        courseDetail.setCourse(objectMapper.convertValue(courses, CourseDto.class));
        return courseDetail;
    }

    @Override
    public CourseDto joinCourse(JoinCourseReq req) {
        Courses courses = iCoursesRepository.findByID(req.getCourseId());
        if (Objects.isNull(courses)) {
            throw new CustomException("Courses not found!");
        }
        StudentDTO studentDetail = iStudentClient.getStudentById(req.getStudentId());
        if (Objects.isNull(studentDetail)) {
            throw new CustomException("Student not found!");
        }
        CoursesMembers coursesMember = new CoursesMembers(courses.getId(), studentDetail.getId());
        iCoursesMembersRepository.save(coursesMember);
        return objectMapper.convertValue(courses, CourseDto.class);
    }
}