5、Spring与Spring Data JPA整合

• Spring Data JPA 由 Spring 所提供，所以Spring Data JPA的所有内容由Spring容器进行管理
• 配置spring配置文件
• 编写实体类，使用jpa注解配置实体类与数据表之间的映射关系
• 编写一个符合Spring Data JPA 的 dao 层接口

添加依赖

使用Spring Data JPA，需要整合Spring与Spring Data JPA，并且需要提供JPA的服务提供者hibernate，所以需要导入spring相关坐标，hibernate坐标，数据库驱动坐标等

<dependencies>
    <!-- junit单元测试 -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.9</version>
        <scope>test</scope>
    </dependency>

    <!-- spring AOP -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.6.8</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <!-- spring 支持 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${spring.version}</version>
    </dependency>

    <!--spring对orm的支持-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>${spring.version}</version>
    </dependency>
      
    <!--hibernate支持-->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>${hibernate.version}</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>${hibernate.version}</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>5.2.1.Final</version>
    </dependency>


    <!-- c3p0-->
    <dependency>
        <groupId>c3p0</groupId>
        <artifactId>c3p0</artifactId>
        <version>${c3p0.version}</version>
    </dependency>

    <!-- log -->
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>${log4j.version}</version>
    </dependency>

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${slf4j.version}</version>
    </dependency>

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>${slf4j.version}</version>
    </dependency>
      
    <!--mysql驱动-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql.version}</version>
    </dependency>

    <!--Spring data jpa 的支持 -->
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
        <version>1.9.0.RELEASE</version>
    </dependency>
    
    <!-- spring对junit的支持-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>4.2.4.RELEASE</version>
    </dependency>

    <!-- 使用spring data jpa 必须引入 -->
    <dependency>
        <groupId>javax.el</groupId>
        <artifactId>javax.el-api</artifactId>
        <version>2.2.4</version>
    </dependency>

    <dependency>
        <groupId>org.glassfish.web</groupId>
        <artifactId>javax.el</artifactId>
        <version>2.2.4</version>
    </dependency>
</dependencies>

添加Spring与Spring Data JPA整合的配置文件

applicationContext.xml 放置于resources目录下

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:task="http://www.springframework.org/schema/task"
       xsi:schemaLocation="
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
		http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
		http://www.springframework.org/schema/data/jpa
		http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">

    <!-- 1.dataSource 配置数据库连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver" />
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/test" />
        <property name="user" value="root" />
        <property name="password" value="12345" />
    </bean>

    <!-- 2.配置entityManagerFactory -->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!--配置扫描的包（实体类所在的包），得到实体类与数据表的映射关系-->
        <property name="packagesToScan" value="com.example.pojo" />
        <!--jpa实现厂家，获取JPA接口接口的实现-->
        <property name="persistenceProvider">
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider" />
        </property>
        <!--JPA的供应商适配器-->
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <!--配置是否自动创建数据库表-->
                <property name="generateDdl" value="false" />
                <!--指定数据库类型-->
                <property name="database" value="MYSQL" />
                <!--数据库方言（特有语法的支持，例如Oracle不支持limit）-->
                <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                <!--是否显示sql-->
                <property name="showSql" value="true" />
            </bean>
        </property>
        <!--注入jpa的配置信息
            加载jpa的基本配置信息和jpa实现方式（Hibernate）的配置信息
                create: 每次都会重新创建数据库表
                update：有表不会重新创建没有反之
        -->
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
        <!--jpa方言，相当于拥有Hibernate的一些高级特性（如1级缓存，2级缓存）-->
        <property name="jpaDialect">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
        </property>
    </bean>


    <!-- 3.事务管理器-->
    <!-- JPA事务管理器  -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

    <!-- 整合spring data jpa-->
    <jpa:repositories base-package="com.example.dao"
                      transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>

    <!-- 4.txAdvice-->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="save*" propagation="REQUIRED"/>
            <tx:method name="insert*" propagation="REQUIRED"/>
            <tx:method name="update*" propagation="REQUIRED"/>
            <tx:method name="delete*" propagation="REQUIRED"/>
            <tx:method name="get*" read-only="true"/>
            <tx:method name="find*" read-only="true"/>
            <tx:method name="*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>

    <!-- 5.aop-->
    <aop:config>
        <aop:pointcut id="pointcut" expression="execution(* com.example.service.*.*(..))" />
        <aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />
    </aop:config>
    
    <!--组件扫描-->
    <context:component-scan base-package="com.example"></context:component-scan>
    
</beans>

使用JPA注解配置映射关系

package com.example.pojo;

import javax.persistence.*;

/**
 * 1.实体类和表的映射关系
 *      @Entity
 *      @Table
 * 2.类中属性和表中字段的映射关系
 *      @Id
 *      @GeneratedValue
 *      @Column
 */
@Entity
@Table(name="users")
public class Users {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "user_id")
    private Integer userId;
    @Column(name = "user_name")
    private String userName;
    @Column(name = "gender")
    private String gender;

    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 String getGender() {
        return gender;
    }

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

    @Override
    public String toString() {
        return "Users{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", gender='" + gender + '\'' +
                '}';
    }
}

编写符合Spring Data JPA规范的Dao层接口

使用Spring Data JPA，只需要按照框架的规范提供dao接口，不需要实现类就可以完成数据库的增删改查、分页查询等方法的定义，极大的简化了我们的开发过程。

/**
 * 符合Spring Data Jpa 的 dao层接口规范
 *      JpaRepository<操作的实体类类型，实体类中主键属性的类型>
 *          #封装了基本CRUD操作
 *      JpaSpecificationExecutor <操作的实体类类型>
 *          #封装了复杂查询（分页）
 */
public interface UsersDao extends JpaRepository<Users, Integer>,JpaSpecificationExecutor<Users>{
}

测试

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")//指定spring容器的配置信息
public class UsersDaoTest {
    @Autowired
    private UsersDao usersDao;

    @Test
    public void testSave(){
        Users users = new Users();
        users.setUserName("小陈");

        usersDao.save(users);
    }
}