Spring boot整合JPA进行CRUD

前言
系列博客
本博客的实现demo
环境配置
- 1.POM依赖
- 2.application.yml文件
- 完整的项目结构
代码实现
- 实体类
- 启动类
- 创建数据访问层
- - 使用Spring Data JPA 创建带条件的CRUD
- 编写业务层
- 创建UserController类
运行测试
- 插入用户数据
- 删除用户数据
- 修改数据
- 查询数据
- 根据手机号查询
总结
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前言

最近是在项目中使用到了Spring Data JPA来减少大量重复SQL语句的编写，能够感觉到的确是使用起来很方便效率也比较高。Spring Data JPA 能够简化数据访问层的实现，让工程师不必去写一些CRUD的接口和实现。Spring Data JPA 自动提供CRUD的实现，能够部分解放工程师们的工作量。

通过本篇博客可以实现使用JPA进行CRUD

系列博客

Spring Data JPA之自动创建数据库表

本博客的实现demo

spring-data-jpa-crud demo

环境配置

创建一个Maven项目并引入依赖

1.POM依赖

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.3.12.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<dependencies>
		<!--spring boot 启动器-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
		<!--spring mvc-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<!--spring boot 开发工具-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</dependency>

		<!--spring boot 测试工具-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

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

		<!--mysql连接器-->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>
	</dependencies>

2.application.yml文件

server:
  port: 8099
spring:
  application:
    name: spring-data-jpa
  datasource:
    #mysq 驱动
    driver-class-name: com.mysql.cj.jdbc.Driver
    #连接数据库的url中配置ip和数据库名称以及时区
    url: jdbc:mysql://localhost:3306/spring_jpa?serverTimezone=Asia/Shanghai&characterEncoding=utf-8
    username: root
    password: root
  jpa:
    hibernate:
      #更新或者创建数据库表结构
      ddl-auto: update
    #控制台显示SQL
    show-sql: true

完整的项目结构

比较典型的MVC项目结构，在JPA里面将熟悉的dao层数据操作层用repository来命名

在这里插入图片描述

代码实现

实体类

目前有一个实体类，一个基础类（用于抽象出一些公共的字段）
基础类BaseEntity

import org.springframework.format.annotation.DateTimeFormat;

import javax.persistence.Column;
import javax.persistence.MappedSuperclass;
import java.util.Date;

/**
 * @author : [WangWei]
 * @version : [v1.0]
 * @className : BaseEntity
 * @description : [基础类]
 * @createTime : [2022/11/18 15:32]
 * @updateUser : [WangWei]
 * @updateTime : [2022/11/18 15:32]
 * @updateRemark : [描述说明本次修改内容]
 */
//@MappedSuperclass的类将不是一个完整的实体类，他将不会映射到数据库表，但是他的属性都将映射到其子类的数据库字段中。
@MappedSuperclass

public class BaseEntity {


 	//定义字段以及字段的类型和长度和是否允许为null
    @Column(name = "create_by",columnDefinition = "varchar(32) COMMENT '创建人'",nullable = false)
    private String createdBy;

    @Column(name = "created_id",columnDefinition = "varchar(32) COMMENT '创建人id'",nullable = false)
    private Long createdId;



    @Column(name = "create_time",nullable = false,columnDefinition = "DATETIME DEFAULT CURRENT_TIMESTAMP  COMMENT '创建时间'")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date createTime;

    @Column(name = "updated_by",columnDefinition = "varchar(32) COMMENT '更新人'")
    private String updateBy;
    @Column(name = "updated_id",columnDefinition = "varchar(32) COMMENT '更新人id'")
    private Long updateId;

	定义字段以及字段的类型并默认为当前时间，并当进行修改的时候更新时间为当前实现
    @Column(name = "update_time",columnDefinition = "DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间'")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date updateTime;
    @Column(name = "is_delete",columnDefinition = "tinyint(1) COMMENT '是否删除(0/1 未删除/删除)'")
    private int isDelete=0;
    @Column(name = "remark",columnDefinition = "varchar(64) COMMENT '备注'")
    private String remark;

    public String getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(String createdBy) {
        this.createdBy = createdBy;
    }


    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public String getUpdateBy() {
        return updateBy;
    }

    public void setUpdateBy(String updateBy) {
        this.updateBy = updateBy;
    }

    public Long getCreatedId() {
        return createdId;
    }

    public void setCreatedId(Long createdId) {
        this.createdId = createdId;
    }

    public Long getUpdateId() {
        return updateId;
    }

    public void setUpdateId(Long updateId) {
        this.updateId = updateId;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }

    public int getIsDelete() {
        return isDelete;
    }

    public void setIsDelete(int isDelete) {
        this.isDelete = isDelete;
    }

    public String getRemark() {
        return remark;
    }

    public void setRemark(String remark) {
        this.remark = remark;
    }
}

实体类UserEntity

import org.springframework.format.annotation.DateTimeFormat;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * @author : [WangWei]
 * @version : [v1.0]
 * @className : UserEntity
 * @description : [用户实体类]
 * @createTime : [2022/11/18 14:57]
 * @updateUser : [WangWei]
 * @updateTime : [2022/11/18 14:57]
 * @updateRemark : [描述说明本次修改内容]
 */
@Entity //声明类为实体类
@Table(name="jpa_user")//对应创建之后的表名
public class UserEntity extends BaseEntity{
    @Id
    @Column(name = "user_code",columnDefinition = "bigint(20) COMMENT '学号'",nullable = false)//定义字段名和类型以及长度和备注，和是否允许为null
    private Long id;

    @Column(name="user_Name",nullable = false,columnDefinition = "varchar(32) COMMENT '用户名'")
    private String userName;
    @Column(name="pass_word",nullable = false,columnDefinition = "varchar(32) COMMENT '密码'")
    private String password;
    @Column(name="phone_Number",nullable = false,columnDefinition = "varchar(16) COMMENT '手机号'")
    private String phoneNumber;
    @Column(name="sex",columnDefinition = "varchar(2) COMMENT '性别'")
    private String sex;
    @Column(name="birthday",nullable = false,columnDefinition = "datetime COMMENT '生日日期'")
    @DateTimeFormat(pattern = "yyyy-MM-dd ")
    private Date birthday;

	


    public Long getId() {
        return id;
    }

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

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassword() {
        return password;
    }

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

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
}

启动类

此时已经可以直接运行启动类，启动程序时候在数据库中会直接生成相应的表。

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringDataJpaApplication {

	public static void main(String[] args) {
		SpringApplication.run(SpringDataJpaApplication.class, args);
	}

}

可以在mysql中查看，或者在Navicat上查看到已经创建的表
在这里插入图片描述

创建数据访问层

在repository中创建UserRepository接口继承JpaRepository接口，JpaRepository接口提供了一些的增删改查的方法。
JpaRepository接口

@NoRepositoryBean
public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> {

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.repository.CrudRepository#findAll()
	 */
	@Override
	List<T> findAll();

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.repository.PagingAndSortingRepository#findAll(org.springframework.data.domain.Sort)
	 */
	@Override
	List<T> findAll(Sort sort);

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.repository.CrudRepository#findAll(java.lang.Iterable)
	 */
	@Override
	List<T> findAllById(Iterable<ID> ids);

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.repository.CrudRepository#save(java.lang.Iterable)
	 */
	@Override
	<S extends T> List<S> saveAll(Iterable<S> entities);

	/**
	 * Flushes all pending changes to the database.
	 */
	void flush();

	/**
	 * Saves an entity and flushes changes instantly.
	 *
	 * @param entity
	 * @return the saved entity
	 */
	<S extends T> S saveAndFlush(S entity);

	/**
	 * Deletes the given entities in a batch which means it will create a single {@link Query}. Assume that we will clear
	 * the {@link javax.persistence.EntityManager} after the call.
	 *
	 * @param entities
	 */
	void deleteInBatch(Iterable<T> entities);

	/**
	 * Deletes all entities in a batch call.
	 */
	void deleteAllInBatch();

	/**
	 * Returns a reference to the entity with the given identifier. Depending on how the JPA persistence provider is
	 * implemented this is very likely to always return an instance and throw an
	 * {@link javax.persistence.EntityNotFoundException} on first access. Some of them will reject invalid identifiers
	 * immediately.
	 *
	 * @param id must not be {@literal null}.
	 * @return a reference to the entity with the given identifier.
	 * @see EntityManager#getReference(Class, Object) for details on when an exception is thrown.
	 */
	T getOne(ID id);

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example)
	 */
	@Override
	<S extends T> List<S> findAll(Example<S> example);

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.repository.query.QueryByExampleExecutor#findAll(org.springframework.data.domain.Example, org.springframework.data.domain.Sort)
	 */
	@Override
	<S extends T> List<S> findAll(Example<S> example, Sort sort);
}

UserRepository接口

import com.example.springdatajpa.entity.UserEntity;
import org.springframework.data.jpa.repository.JpaRepository;

/**
 * @author : [WangWei]
 * @version : [v1.0]
 * @className : UserRepository
 * @description : [User数据访问接口]
 * @createTime : [2022/11/19 19:15]
 * @updateUser : [WangWei]
 * @updateTime : [2022/11/19 19:15]
 * @updateRemark : [描述说明本次修改内容]
 */
public interface UserRepository extends JpaRepository<UserEntity,Long> {

}

JpaRepository<T, ID>T表示实体的类型，ID表示实体类中ID的类型。

使用Spring Data JPA 创建带条件的CRUD

由于JpaRepository<T, ID>接口只定义了一些较为简单的CRUD，但是对于一些带条件的CRUDJpaRepository并没有给出，但是我们可以在继承JpaRepository<T, ID>接口的接口中创建相应的方法。

import com.example.springdatajpa.entity.UserEntity;
import org.springframework.data.jpa.repository.JpaRepository;

/**
 * @author : [WangWei]
 * @version : [v1.0]
 * @className : UserRepository
 * @description : [描述说明该类的功能]
 * @createTime : [2022/11/19 19:15]
 * @updateUser : [WangWei]
 * @updateTime : [2022/11/19 19:15]
 * @updateRemark : [描述说明本次修改内容]
 */
public interface UserRepository extends JpaRepository<UserEntity,Long> {

    /*
     * @version V1.0
     * Title: findUserEntitiesByPhoneNumberAndIsDelete
     * @author Wangwei
     * @description 根据手机号查询
     * @createTime  2022/11/20 10:00
     * @param [phoneNumber, isDelete]
     * @return com.example.springdatajpa.entity.UserEntity
     */
    UserEntity findUserEntitiesByPhoneNumberAndIsDelete(String phoneNumber,int isDelete);

    
}

创建相应的方法，先定义方法的返回值，在定义操作类型（find，delete，search）+By+条件
在这里插入图片描述

如果有需要可以参考Spring Data Jpa官网上Spring Data Jpa

编写业务层

UserSerivce接口

import com.example.springdatajpa.entity.UserEntity;

import java.util.List;

/**
 * @author : [WangWei]
 * @version : [v1.0]
 * @className : UserSerivce
 * @description : [User业务层接口]
 * @createTime : [2022/11/19 20:27]
 * @updateUser : [WangWei]
 * @updateTime : [2022/11/19 20:27]
 * @updateRemark : [描述说明本次修改内容]
 */
public interface UserSerivce {

    //新增用户
    UserEntity insertUser(UserEntity user);

    //删除用户
    void deleteUser(Long id);

    //修改用户信息
    UserEntity updateUser(UserEntity user);

    //查询所有用户
    List<UserEntity> queryUser();

    //根据手机号查询用户信息
    UserEntity queryUserByPhoneNumber(UserEntity user);
}

UserServiceImpl实现类

import com.example.springdatajpa.entity.UserEntity;
import com.example.springdatajpa.repository.UserRepository;
import com.example.springdatajpa.service.UserSerivce;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author : [WangWei]
 * @version : [v1.0]
 * @className : UserServiceImpl
 * @description : [User业务实现类]
 * @createTime : [2022/11/19 20:33]
 * @updateUser : [WangWei]
 * @updateTime : [2022/11/19 20:33]
 * @updateRemark : [描述说明本次修改内容]
 */
@Service
public class UserServiceImpl implements UserSerivce {

    //User数据访问接口
    @Resource
    UserRepository userRepository;
    /*
     * @version V1.0 
     * Title: insertUser
     * @author Wangwei 
     * @description 插入用户信息
     * @createTime  2022/11/20 8:47
     * @param [user] 
     * @return com.example.springdatajpa.entity.UserEntity
     **/
    @Override
    public UserEntity insertUser(UserEntity user) {
       return userRepository.save(user);
    }

    /*
     * @version V1.0 
     * Title: deleteUser
     * @author Wangwei 
     * @description 根据id删除用户信息
     * @createTime  2022/11/20 8:48
     * @param [id] 
     * @return void
     */
    @Override
    public void deleteUser(Long id) {
        userRepository.deleteById(id);
    }

    /*
     * @version V1.0 
     * Title: updateUser
     * @author Wangwei 
     * @description 修改用户信息，save方法是如果存在这条数据则进行修改否则进行新增
     * @createTime  2022/11/20 8:49
     * @param [user] 
     * @return com.example.springdatajpa.entity.UserEntity
     **/
    @Override
    public UserEntity updateUser(UserEntity user) {
        return userRepository.save(user);
    }

    /*
     * @version V1.0 
     * Title: queryUser
     * @author Wangwei 
     * @description 查询所有用户
     * @createTime  2022/11/20 8:50
     * @param [] 
     * @return java.util.List<com.example.springdatajpa.entity.UserEntity>
     */
    @Override
    public List<UserEntity> queryUser() {
        return userRepository.findAll();
    }
	/*
     * @version V1.0
     * Title: queryUserByPhoneNumber
     * @author Wangwei
     * @description 通过手机号查询用户信息
     * @createTime  2022/11/20 8:50
     * @param [user]
     * @return com.example.springdatajpa.entity.UserEntity
     * */
    @Override
    public UserEntity queryUserByPhoneNumber(UserEntity user) {
        return userRepository.findUserEntitiesByPhoneNumberAndIsDelete(user.getPhoneNumber(),0);
    }

创建UserController类

import com.example.springdatajpa.entity.UserEntity;
import com.example.springdatajpa.service.UserSerivce;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author : [WangWei]
 * @version : [v1.0]
 * @className : UserController
 * @description : [User控制层类]
 * @createTime : [2022/11/19 20:40]
 * @updateUser : [WangWei]
 * @updateTime : [2022/11/19 20:40]
 * @updateRemark : [描述说明本次修改内容]
 */
@RestController
@RequestMapping("/user")
public class UserController {

    //注入业务接口
    @Resource
    UserSerivce userSerivce;
    /*
     * @version V1.0
     * Title: insertUser
     * @author Wangwei
     * @description 新增用户
     * @createTime  2022/11/20 8:54
     * @param [user]
     * @return UserEntity
     */
    @PostMapping("/insert")
    public UserEntity insertUser(@RequestBody UserEntity user){
        return userSerivce.insertUser(user);
    }

    /*
     * @version V1.0
     * Title: deleteUser
     * @author Wangwei
     * @description 通过id删除用户
     * @createTime  2022/11/20 8:56
     * @param [id]
     * @return void
     */
    @DeleteMapping("delete/{id}")
    public void deleteUser(@PathVariable("id") Long id){
        userSerivce.deleteUser(id);
    }

    /*
     * @version V1.0
     * Title: updateUser
     * @author Wangwei
     * @description:修改用户信息
     * @createTime  2022/11/20 8:57
     * @param [user]
     * @return com.example.springdatajpa.entity.UserEntity
     * */
    @PutMapping("/update")
    public UserEntity updateUser(@RequestBody UserEntity user){
        return userSerivce.updateUser(user);
    }

    /*
     * @version V1.0
     * Title: queryUser
     * @author Wangwei
     * @description 查询所有用户信息
     * @createTime  2022/11/20 9:25
     * @param []
     * @return java.util.List<com.example.springdatajpa.entity.UserEntity>
     */
    @GetMapping("/query")
    public List<UserEntity> queryUser(){
        return userSerivce.queryUser();
    }

    @GetMapping("/query/{phoneNumber}")
    public UserEntity queryUserByPhoneNumber(@PathVariable("phoneNumber") String phoneNumber){
        return userSerivce.queryUserByPhoneNumber(phoneNumber);
    }

}

运行测试

选择使用postman进行调用接口测试

插入用户数据

{
        "createdBy": "wangwei",
        "createdId": 3,
        "createTime": "2022-11-20T02:20:08.000+00:00",
        "updateBy": "wangwei",
        "updateId": 3,
        "updateTime": "2022-11-20T02:20:08.000+00:00",
        "isDelete": 0,
        "remark": null,
        "id": 1,
        "userName": "wangwei",
        "password": "003",
        "phoneNumber": "110",
        "sex": "男",
        "birthday": "2022-11-20T02:19:40.000+00:00"
    }