SpringBoot整合spring-data-jpa

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SpringBoot整合spring-data-jpa

jpa 是JavaEE定义的一种规范，常用的实现一般是 Hibernate，而 spring-data-jpa 则是对jpa的又一层封装，提供了更多便捷的方法。

这里不会深入讲解spring-data-jpa的使用，只是讲解怎么快速的整合使用，目的是帮助那些想学，但是在整合上老是翻车的同学

导入依赖

<dependency>
	<groupId>com.zaxxer</groupId>
	<artifactId>HikariCP</artifactId>
</dependency>
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

配置

spring:
  data:
    jpa:
      repositories:
        # 开启jpa
        enabled: true
        bootstrap-mode: default
  jpa:
    # 数据库方言
    database-platform: org.hibernate.dialect.MySQL57Dialect
    open-in-view: false
    # 打印SQL
    show-sql: false
    properties:
      # 格式化输出的SQL语句
      hibernate.format_sql: false
    hibernate:
      # 自动建表策略
      ddl-auto: update

这里忽略了数据源的配置

关于自动建表策略

# 枚举值
spring.jpa.hibernate.ddl-auto
create				不管表是否存在, 每次启动都会重新建表(会导致数据丢失)
create-drop			启动的时候创建表, 程序退出(SessionFactory关闭)的时候删除表
none				不进行任何操作
update				如果数据表不存在则创建, 在实体对象被修改后,下次启动重新修改表结构(不会删除已经存在的数据)
validate			启动的时候验证数据表的结构,

相关的配置类

这里仅仅列出了部分常用的配置，如果需要了解所有的配置信息，可以参考配置类

  • JpaProperties (spring.jpa)
  • SpringDataWebProperties (spring.data.web)
  • HibernateProperties (spring.jpa.hibernate)

相关配置的文档
https://docs.spring.io/spring-boot/docs/current/reference/html/appendix-application-properties.html#data-properties

定义实体类

User

import java.io.Serializable;
import java.time.LocalDateTime;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Enumerated;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Index;
import javax.persistence.Table;

// 指定表名称
@Table(name = "user", indexes = {
	// 定义索引
	@Index(columnList = "account", unique = true) 
})
// 标识实体类
@Entity
// 设置表注释
@org.hibernate.annotations.Table(appliesTo = "user", comment = "用户")
public class User implements Serializable {

	/**
	 * 
	 */
	private static final long serialVersionUID = 4953012795378725917L;

	@Id // id 字段
	@Column(columnDefinition = "INT(11) UNSIGNED COMMENT 'id'")
	@GeneratedValue(strategy = GenerationType.IDENTITY) // 自增
	private Integer id;

	// 账户
	@Column(columnDefinition = "VARCHAR(50) COMMENT '登录账户'", nullable = false)
	private String account;

	// 密码
	@Column(columnDefinition = "VARCHAR(255) COMMENT '登录密码'", nullable = false)
	private String password;

	// 性别
	@Column(columnDefinition = "TINYINT(1) COMMENT '性别。0：男，1：女'", nullable = false)
	@Enumerated
	private Gender gender;

	// 创建时间
	@Column(name = "created_date", columnDefinition = "timestamp DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间'", nullable = false)
	private LocalDateTime createdDate;

	// 最后修改时间
	@Column(name = "last_modified_date", columnDefinition = "timestamp NULL DEFAULT NULL COMMENT '最后一次修改时间'")
	private LocalDateTime lastModifiedDate;

	// 记录状态
	@Column(columnDefinition = "TINYINT(1) unsigned COMMENT '是否启用'", nullable = false)
	private Boolean enabled;

	public Integer getId() {
		return id;
	}

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

	public String getAccount() {
		return account;
	}

	public void setAccount(String account) {
		this.account = account;
	}

	public String getPassword() {
		return password;
	}

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

	public Gender getGender() {
		return gender;
	}

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

	public LocalDateTime getCreatedDate() {
		return createdDate;
	}

	public void setCreatedDate(LocalDateTime createdDate) {
		this.createdDate = createdDate;
	}

	public LocalDateTime getLastModifiedDate() {
		return lastModifiedDate;
	}

	public void setLastModifiedDate(LocalDateTime lastModifiedDate) {
		this.lastModifiedDate = lastModifiedDate;
	}

	public Boolean getEnabled() {
		return enabled;
	}

	public void setEnabled(Boolean enabled) {
		this.enabled = enabled;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", account=" + account + ", password=" + password + ", gender=" + gender
				+ ", createdDate=" + createdDate + ", lastModifiedDate=" + lastModifiedDate + ", enabled=" + enabled
				+ "]";
	}

	public static enum Gender {
		BOY, GIRL
	}
}

Repository

抽象出BaseRepository

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.repository.NoRepositoryBean;

@NoRepositoryBean  // 该接口不是一个Repository，不需要生成代理实现
public interface BaseRepository <T, ID> extends JpaRepository<T, ID>, JpaSpecificationExecutor <T>
																				// , QuerydslPredicateExecutor<T>  如果使用了QueryDSL还可以实现这个接口
{

}

定义 UserRepository

import io.springboot.jpa.entity.User;

public interface UserRepository extends BaseRepository<User, Integer> {

}

Service

抽象出 BaseService

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

public interface BaseService<T, ID> extends JpaRepository<T, ID>, JpaSpecificationExecutor <T>
														// , QuerydslPredicateExecutor<T>  
{

}

抽象出 AbstractService

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


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Example;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.transaction.annotation.Transactional;


import io.springboot.jpa.repository.BaseRepository;




public abstract class AbstractService<T, ID> implements BaseService <T, ID> {

	/**
	 * 泛型注入
	 */
	@Autowired
	protected BaseRepository<T, ID> baseRepository;

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public List<T> findAll() {
		return this.baseRepository.findAll();
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public List<T> findAll(Sort sort) {
		return this.baseRepository.findAll(sort);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public List<T> findAllById(Iterable<ID> ids) {
		return this.baseRepository.findAllById(ids);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public <S extends T> List<S> saveAll(Iterable<S> entities) {
		return this.baseRepository.saveAll(entities);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public void flush() {
		this.baseRepository.flush();
	}

	@Transactional(rollbackFor = Throwable.class)
	public <S extends T> S saveAndFlush(S entity) {
		return this.baseRepository.saveAndFlush(entity);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public void deleteInBatch(Iterable<T> entities) {
		this.baseRepository.deleteInBatch(entities);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public void deleteAllInBatch() {
		this.baseRepository.deleteAllInBatch();
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public T getOne(ID id) {
		return this.baseRepository.getOne(id);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public <S extends T> List<S> findAll(Example<S> example) {
		return this.baseRepository.findAll(example);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public <S extends T> List<S> findAll(Example<S> example, Sort sort) {
		return this.baseRepository.findAll(example, sort);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public Page<T> findAll(Pageable pageable) {
		return this.baseRepository.findAll(pageable);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public <S extends T> S save(S entity) {
		return this.baseRepository.save(entity);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public Optional<T> findById(ID id) {
		return this.baseRepository.findById(id);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public boolean existsById(ID id) {
		return this.baseRepository.existsById(id);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public long count() {
		return this.baseRepository.count();
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public void deleteById(ID id) {
		this.baseRepository.deleteById(id);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public void delete(T entity) {
		this.baseRepository.delete(entity);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public void deleteAll(Iterable<? extends T> entities) {
		this.baseRepository.deleteAll(entities);
	}

	@Override
	@Transactional(rollbackFor = Throwable.class)
	public void deleteAll() {
		this.baseRepository.deleteAll();
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public <S extends T> Optional<S> findOne(Example<S> example) {
		return this.baseRepository.findOne(example);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public <S extends T> Page<S> findAll(Example<S> example, Pageable pageable) {
		return this.baseRepository.findAll(example, pageable);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public <S extends T> long count(Example<S> example) {
		return this.baseRepository.count(example);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public <S extends T> boolean exists(Example<S> example) {
		return this.baseRepository.exists(example);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public Optional<T> findOne(Specification<T> spec) {
		return this.baseRepository.findOne(spec);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public List<T> findAll(Specification<T> spec) {
		return this.baseRepository.findAll(spec);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public Page<T> findAll(Specification<T> spec, Pageable pageable) {
		return this.baseRepository.findAll(spec, pageable);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public List<T> findAll(Specification<T> spec, Sort sort) {
		return this.baseRepository.findAll(spec, sort);
	}

	@Override
	@Transactional(readOnly = true, rollbackFor = Throwable.class)
	public long count(Specification<T> spec) {
		return this.baseRepository.count(spec);
	}
}

定义 UserService

import org.springframework.stereotype.Service;

import io.springboot.jpa.entity.User;

@Service
public class UserService extends AbstractService<User, Integer> {
	
}

添加注解驱动

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@EnableJpaRepositories(basePackages = { "io.springboot.jpa.repository" })
@EntityScan(basePackages = { "io.springboot.jpa.entity" })
public class JpaApplication {
	public static void main(String[] args) {
		SpringApplication.run(JpaApplication.class, args);
	}
}

@EnableJpaRepositories 指定 repository 所在的包
@EntityScan 指定entity 所在的包

测试

import io.springboot.jpa.JpaApplication;
import io.springboot.jpa.entity.User;
import io.springboot.jpa.service.UserService;

import java.time.LocalDateTime;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = JpaApplication.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class JpaApplicationTest {
	
	static final Logger LOGGER = LoggerFactory.getLogger(JpaApplicationTest.class);
	
	@Autowired
	UserService userService;
	
	@Test
	public void test () {
		// 存储
		User user = new User();
		user.setAccount("kevinblandy.cn@gmail.com");
		user.setPassword("123456");
		user.setGender(User.Gender.GIRL);
		user.setEnabled(Boolean.TRUE);
		user.setCreatedDate(LocalDateTime.now());
		
		this.userService.save(user);
		
		LOGGER.info("save success.....");
		
		// 检索
		User results = this.userService.findById(user.getId()).orElseGet(null);
		LOGGER.info("query result={}", results);
	}
}

自动创建的表

CREATE TABLE `user` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT 'id',
  `account` varchar(50) NOT NULL COMMENT '登录账户',
  `created_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `enabled` tinyint(1) unsigned NOT NULL COMMENT '是否启用',
  `gender` tinyint(1) NOT NULL COMMENT '性别。0：男，1：女',
  `last_modified_date` timestamp NULL DEFAULT NULL COMMENT '最后一次修改时间',
  `password` varchar(255) NOT NULL COMMENT '登录密码',
  PRIMARY KEY (`id`),
  UNIQUE KEY `UKdnq7r8jcmlft7l8l4j79l1h74` (`account`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='用户';

执行的日志

Hibernate: 
    insert 
    into
        user
        (account, created_date, enabled, gender, last_modified_date, password) 
    values
        (?, ?, ?, ?, ?, ?)
2020-06-23 17:57:36.264  INFO 7612 --- [           main] i.s.jpa.test.JpaApplicationTest          : save success.....
Hibernate: 
    select
        user0_.id as id1_0_0_,
        user0_.account as account2_0_0_,
        user0_.created_date as created_3_0_0_,
        user0_.enabled as enabled4_0_0_,
        user0_.gender as gender5_0_0_,
        user0_.last_modified_date as last_mod6_0_0_,
        user0_.password as password7_0_0_ 
    from
        user user0_ 
    where
        user0_.id=?
2020-06-23 17:57:36.303  INFO 7612 --- [           main] i.s.jpa.test.JpaApplicationTest          : query result=User [id=1, account=kevinblandy.cn@gmail.com, password=123456, gender=GIRL, createdDate=2020-06-23T17:57:36, lastModifiedDate=null, enabled=true]

最后

整合的步骤

  • 添加依赖
  • 添加配置
  • 定义实体类
  • 定义Repositroy
  • 定义Servive
  • 添加注解驱动，指定Repositroy和实体类的路径

JPA + QueryDSL才是最佳搭档

单纯的用JPA，局限还是蛮多，不够灵活。但是配合QueryDsl，一切都会不一样。有空我会专门写这个教程。感受到QueryDsl魅力后，保证你从此都不会在用MyBatis（我就是 :eyes:）