Spring Data JPA：Spring Data JPA 是 spring data 项目下的一个模块。提供了一套基于 JPA标准操作数据库的简化方案。底层默认的是依赖 Hibernate JPA 来实现的。
Spring Data JPA 的技术特点：我们只需要定义接口并集成 Spring Data JPA 中所提供的接口就可以了。不需要编写接口实现类。
SpringDataJPA
一、接口继承结构
在搭建入门案例之前我们先来看下SpringDataJPA中所需要使用到的几个接口的继承结构图，便于我们后面的分析。
二、入门案例
我们先通过JpaRepoistry接口来快速实现一个添加操作
1.创建maven项目
创建一个简单的maven项目即可
2.添加相关依赖
基础依赖和前面介绍的hibernateJPA是一样的，额外再添加SpringDataJPA的依赖即可，具体如下:
<dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.3.21.RELEASE</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> <version>1.6.8.RELEASE</version> </dependency> <dependency> <groupId>com.mchange</groupId> <artifactId>c3p0</artifactId> <version>0.9.5.3</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>5.0.7.Final</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>4.3.21.RELEASE</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.32</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>4.3.21.RELEASE</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>5.0.7.Final</version> </dependency> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-jpa</artifactId> <version>1.9.0.RELEASE</version> </dependency> </dependencies>
3.添加配置文件
一个数据库的配置文件及spring的配置文件，注意添加jps的schema。如下:
jdbc.url=jdbc:mysql://localhost:3306/ssm?characterEncoding=utf-8 jdbc.driver.class=com.mysql.jdbc.Driver jdbc.username=root jdbc.password=123456
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jpa="http://www.springframework.org/schema/data/jpa" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"> <!-- 配置读取properties文件的工具类 --> <context:property-placeholder location="classpath:jdbc.properties"/> <!-- 配置c3p0数据库连接池 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="jdbcUrl" value="${jdbc.url}"/> <property name="driverClass" value="${jdbc.driver.class}"/> <property name="user" value="${jdbc.username}"/> <property name="password" value="${jdbc.password}"/> </bean> <!-- Spring 整合 JPA 配置 EntityManagerFactory--> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSource"/> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <!-- hibernate 相关的属性的注入 --> <!-- 配置数据库类型 --> <property name="database" value="MYSQL"/> <!-- 正向工程 自动创建表 --> <property name="generateDdl" value="true"/> <!-- 显示执行的 SQL --> <property name="showSql" value="true"/> </bean> </property> <!-- 扫描实体的包 --> <property name="packagesToScan"> <list> <value>com.dpb.pojo</value> </list> </property> </bean> <!-- 配置 Hibernate 的事务管理器 --> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory"/> </bean> <!-- 配置开启注解事务处理 --> <tx:annotation-driven transaction-manager="transactionManager"/> <!-- 配置springIOC的注解扫描 --> <context:component-scan base-package="com.dpb"/> <!-- Spring Data JPA 的配置 --> <!-- base-package：扫描 dao 接口所在的包 --> <jpa:repositories base-package="com.dpb.dao"/> </beans>
4.创建pojo和Dao接口
创建pojo类Users和Dao接口如下:
package com.dpb.pojo; import javax.persistence.*; import java.io.Serializable; /** * @program: spring-hibernate-jpa * @description: Users的Pojo对象 * @author: 波波烤鸭 * @create: 2019-05-18 09:37 */ @Entity @Table(name="users") public class Users implements Serializable { @Id @GeneratedValue(strategy= GenerationType.IDENTITY)//strategy=GenerationType.IDENTITY 自增长 @Column(name="userid") private Integer userid; @Column(name="username") private String username; @Column(name="userage") private Integer userage; public Integer getUserid() { return userid; } public void setUserid(Integer userid) { this.userid = userid; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public Integer getUserage() { return userage; } public void setUserage(Integer userage) { this.userage = userage; } @Override public String toString() { return "Users [userid=" + userid + ", username=" + username + ", userage=" + userage + "]"; } }
/** * SpringDataJPA 实现JpaRepository * 泛型 第一个参数是对应的Pojo类型 * 第二个参数是注解的包装类型 */ public interface UserDao extends JpaRepository<Users,Integer> { }
5.单元测试
/** * @program: spring-data-jpa * @description: 单元测试 * @author: 波波烤鸭 * @create: 2019-05-18 09:48 */ @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration("classpath:applicationContext.xml") public class TestDemo { @Autowired private UserDao usersDao; /** * 添加用户 */ @Test @Transactional// 在测试类对于事务提交方式默认的是回滚。 @Rollback(false)//取消自动回滚 public void testInsertUsers(){ Users users = new Users(); users.setUserage(20); users.setUsername("张三-jpa"); this.usersDao.save(users); } }
