SpringBoot整合SpringDataJPA入门案例

第一步，引入pom

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- springBoot JPA的起步依赖 -->
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-jpa -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency> 
        <!-- MySQL连接驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.35</version>
        </dependency>
    </dependencies>

第二步，创建User的pojo

数据库

package com.hikktn.entity;

import javax.persistence.*;
import java.io.Serializable;

/**
 * @ClassName UserEntity
 * @Description TODO
 * @Author lisonglin
 * @Date 2021/4/2 15:41
 * @Version 1.0
 */
@Entity
@Table(name = "user", schema = "test")
public class UserEntity implements Serializable {
	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	private int id;
	private String username;
	private String password;

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

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

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

	public void setUsername(String username) {
		this.username = username;
	}

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

	public void setPassword(String password) {
		this.password = password;
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) return true;
		if (o == null || getClass() != o.getClass()) return false;

		UserEntity that = (UserEntity) o;

		if (id != that.id) return false;
		if (username != null ? !username.equals(that.username) : that.username != null) return false;
		if (password != null ? !password.equals(that.password) : that.password != null) return false;

		return true;
	}

	@Override
	public int hashCode() {
		int result = id;
		result = 31 * result + (username != null ? username.hashCode() : 0);
		result = 31 * result + (password != null ? password.hashCode() : 0);
		return result;
	}

	@Override
	public String toString() {
		return "UserEntity{" + "id=" + id + ", username='" + username + '\'' + ", password='" + password + '\'' + '}';
	}
}

第三步，实现接口

package com.hikktn.repository;

import com.hikktn.entity.UserEntity;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

import java.util.List;

/**
 * @ClassName UserRepository
 * @Description TODO
 * @Author lisonglin
 * @Date 2021/4/2 16:00
 * @Version 1.0
 */
public interface UserRepository extends JpaRepository<UserEntity, Integer>, JpaSpecificationExecutor<UserEntity> {

	// 查询全部
	List<UserEntity> findAll();

}

第四步，测试

package com.hikktn.test;

import com.hikktn.MySpringBootApplication;
import com.hikktn.entity.UserEntity;
import com.hikktn.repository.UserRepository;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;
import java.util.Optional;

/**
 * @ClassName JpaTest
 * @Description TODO
 * @Author lisonglin
 * @Date 2021/4/2 16:02
 * @Version 1.0
 */
@RunWith(SpringRunner.class)
@SpringBootTest(classes= MySpringBootApplication.class)
public class JpaTest {

	@Autowired
	private UserRepository userRepository;

	@Test
	public void testGetUserAll(){
		List<UserEntity> users = userRepository.findAll();
		System.out.println(users);
	}

	@Test
	public void testAddUser(){
		UserEntity userEntity =new UserEntity();
		userEntity.setUsername("tom");
		userEntity.setPassword("123");
		userRepository.save(userEntity);
	}

	@Test
	public void testFindOneUser(){
		Optional<UserEntity> byId = userRepository.findById(1);
		System.out.println(byId.get());
	}

	@Test
	public void testDeleteUser() {
		userRepository.deleteById(5);
	}

	@Test
	@Transactional(rollbackFor = Exception.class)
//    @Rollback(value = false)//发生异常不回滚
	public void update(){
		Optional<UserEntity> optional = userRepository.findById(1);
		System.out.println(optional.orElseGet(UserEntity::new));
	}

}

第五步，增删改查

package com.hikktn.controller;

import com.hikktn.entity.UserEntity;
import com.hikktn.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.web.bind.annotation.*;

import java.util.Optional;

/**
 * @ClassName UserController
 * @Description TODO
 * @Author lisonglin
 * @Date 2021/4/2 22:01
 * @Version 1.0
 */
@RestController
@RequestMapping(path = "/user")
public class UserController {

	@Autowired
	private UserRepository userRepository;

	@GetMapping(path = "/all")
	@ResponseBody
	public Iterable<UserEntity> getAllUsers(){
		return userRepository.findAll();
	}

	/*
		增加用户
	 */
	@PostMapping()
	public UserEntity saveUser(@RequestBody UserEntity user) {
		return userRepository.save(user);
	}

	/*
		删除用户
	 */
	@DeleteMapping("/{id}")
	public void deleteUser(@PathVariable("id") int userId) {
		userRepository.deleteById(userId);
	}

	/*
		修改用户
	 */
	@PutMapping("/{id}")
	public UserEntity updateUser(@PathVariable("id") int userId, @RequestBody UserEntity user) {
		user.setId(userId);
		return userRepository.saveAndFlush(user);
	}

	/*
		查询用户
	 */
	@GetMapping("/{id}")
	public UserEntity getUserInfo(@PathVariable("id") int userId) {
		Optional<UserEntity> optional = userRepository.findById(userId);
		return optional.orElseGet(UserEntity::new);
	}

	/*
		分页查询多个用户
	 */
	@GetMapping("/list")
	public Page<UserEntity> pageQuery(@RequestParam(value = "pageNum", defaultValue = "1") Integer pageNum,
	                                  @RequestParam(value = "pageSize", defaultValue = "10") Integer pageSize) {
		return userRepository.findAll(PageRequest.of(pageNum - 1, pageSize));
	}
}

项目地址

链接：https://pan.baidu.com/s/1-1KNBeBRFzGmwW4WUiwYwQ 
提取码：ck9g