Spring Boot, Spring Data JPA, Spring Rest API CRUD

Giới thiệu
Cài đặt
Chạy thử

# Giới thiệu

Trong hướng dẫn này, mình sẽ xây dựng một ví dụ API Spring Boot Rest CRUD với Maven sử dụng Spring Data JPA để tương tác với cơ sở dữ liệu MySQL

Đây là những api trong ví dụ này

Methods	Urls	Actions
POST	/api/employee	Tạo mới employee
GET	/api/employee	Lấy tất cả employee
GET	/api/employee/:id	Lấy employee bằng id
DELETE	/api/employee/:id	Xoá employee bằng id
PUT	/api/employee/:id	Cập nhật employee bằng id

# Cài đặt

Tạo database trong cơ sở dữ liệu MySQL

DROP DATABASE IF EXISTS employeedb;

CREATE DATABASE employeedb;

USE employeedb;

CREATE TABLE employee(
	id INT AUTO_INCREMENT PRIMARY KEY,
        name VARCHAR(50),
        salary float
);

INSERT INTO employee VALUES (1, 'Pham Quang Huy', 50.3);
INSERT INTO employee VALUES (2, 'Pham Xuan Hoai', 80.7);

Cấu trúc source Spring Boot

EmployeeController.java: nhận request, xử lý và trả về dữ liệu

MessageController.java: hỗ trợ tuỳ biến thông điệp trả về

Employee.java: là entity mapping với database

IEmployeeRepository: là repository kế thừa JpaRepository

EmployeeService: là service implement IEmployeeRepository

application.properties: cấu hình hệ thống chính

Đầu tiên, trong pom.xml thêm các dependency

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

application.properties:

# Connect MySQL
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/employeedb
spring.datasource.username=root
spring.datasource.password=root

# Hibernate
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

Trong thư mục entity tạo Employee.java ở đây mình generate từ database các bạn có thể tham khảo Spring Boot generate entity class from MySQL Database using IntelliJ IDEA ULTIMATE

package com.fpt.employeemanagementapi.entities;

import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import java.util.Objects;

@Entity
public class Employee {
    private int id;
    private String name;
    private Double salary;
    private Integer gender;
    private Boolean status;


    public Employee() {
    }

    public Employee(int id, String name, Double salary, Integer gender, Boolean status) {
        this.id = id;
        this.name = name;
        this.salary = salary;
        this.gender = gender;
        this.status = status;
    }

    @Id
    @Column(name = "id")
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Basic
    @Column(name = "name")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Basic
    @Column(name = "salary")
    public Double getSalary() {
        return salary;
    }

    public void setSalary(Double salary) {
        this.salary = salary;
    }

    @Basic
    @Column(name = "gender")
    public Integer getGender() {
        return gender;
    }

    public void setGender(Integer gender) {
        this.gender = gender;
    }

    @Basic
    @Column(name = "status")
    public Boolean getStatus() {
        return status;
    }

    public void setStatus(Boolean status) {
        this.status = status;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Employee employee = (Employee) o;
        return id == employee.id &&
                Objects.equals(name, employee.name) &&
                Objects.equals(salary, employee.salary) &&
                Objects.equals(gender, employee.gender) &&
                Objects.equals(status, employee.status);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, name, salary, gender, status);
    }
}

dto/Message.java

package com.fpt.demojavadocfast.dto;

public class Message {
    String msg;

    public Message() {
    }

    public Message(String msg) {
        this.msg = msg;
    }

    public String getMess() {
        return msg;
    }

    public void setMess(String msg) {
        this.msg = msg;
    }
}

repository/EmployeeRepository.java

package com.fpt.demojavadocfast.repository;

import com.fpt.demojavadocfast.entity.Employee;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface IEmployeeRepository extends JpaRepository<Employee, Integer> {}

service/EmployeeService.java

package com.fpt.demojavadocfast.service;

import com.fpt.demojavadocfast.entity.Employee;
import com.fpt.demojavadocfast.repository.IEmployeeRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class EmployeeService {
    @Autowired
    IEmployeeRepository iEmployeeRepository;

    public List<Employee> findAll(){
        return iEmployeeRepository.findAll();
    }

    public Employee findEmployeeById(int id){
        return iEmployeeRepository.findById(id).get();
    }

    public boolean existById(int id){
        return iEmployeeRepository.existsById(id);
    }

    public void save(Employee employee){
        iEmployeeRepository.save(employee);
    }

    public void deleteById(int id){
        iEmployeeRepository.deleteById(id);
    }
}

controller/EmployeeController.java

Trên class EmployeeController thêm annotaion @CrossOrigin để thông báo cho browser biết domain nào được truy xuất tài nguyên từ server, thiết lập giá trị * để chấp nhận request từ tất cả domain

package com.fpt.demojavadocfast.controller;

import com.fpt.demojavadocfast.dto.Message;
import com.fpt.demojavadocfast.entity.Employee;
import com.fpt.demojavadocfast.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@CrossOrigin("*")
@RequestMapping("/api")
public class EmployeeController {
    @Autowired
    EmployeeService employeeService;

    @GetMapping("/employee")
    public ResponseEntity<List<Employee>> getAllEmployee(){
        try {
            List<Employee> employees = employeeService.findAll();
            return new ResponseEntity(employees, HttpStatus.OK);
        }catch (Exception e){
            return new ResponseEntity(HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }

    @GetMapping("/employee/{id}")
    public ResponseEntity<?> getEmployee(@PathVariable("id") int id){
        try {
            if (employeeService.existById(id)){
                Employee employee = employeeService.findEmployeeById(id);
                return new ResponseEntity(employee, HttpStatus.OK);
            }
            return new ResponseEntity(new Message("Employee not exist!!!"), HttpStatus.BAD_REQUEST);
        }catch (Exception e){
            return new ResponseEntity(HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }

    @DeleteMapping("/employee/{id}")
    public ResponseEntity<?> deleteEmployee(@PathVariable("id") int id){
        try {
            if (employeeService.existById(id)){
                Employee employee = employeeService.findEmployeeById(id);
                employeeService.deleteById(id);
                return new ResponseEntity(employee, HttpStatus.OK);
            }
            return new ResponseEntity(new Message("Employee not exist!!!"), HttpStatus.BAD_REQUEST);
        }catch (Exception e){
            return new ResponseEntity(HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }

    @PostMapping("/employee")
    public ResponseEntity<?> addEmployee(@RequestBody Employee employee){
        try {
            if (!employeeService.existById(employee.getId())){
                Employee employeeNew = new Employee(employee.getId(), employee.getName(), employee.getSalary());
                employeeService.save(employeeNew);
                return new ResponseEntity(employee, HttpStatus.OK);
            }
            return new ResponseEntity(new Message("Employee id is existed!!!"), HttpStatus.BAD_REQUEST);
        }catch (Exception e){
            return new ResponseEntity(HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }

    @PutMapping("/employee")
    public ResponseEntity<?> updateEmployee(@RequestBody Employee employee){
        try {
            if (employeeService.existById(employee.getId())){
                Employee employeeUpdate = employeeService.findEmployeeById(employee.getId());
                employeeUpdate.setName(employee.getName());
                employeeUpdate.setSalary(employee.getSalary());
                employeeService.save(employeeUpdate);
                return new ResponseEntity(employee, HttpStatus.OK);
            }
            return new ResponseEntity(new Message("Employee not exist!!!"), HttpStatus.BAD_REQUEST);
        }catch (Exception e){
            return new ResponseEntity(HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }
}