spring学习笔记整理(四)-----Spring整合Data JPA

Spring整合Data JPA

　　　JPA是Java Persistence API的简称，中文名Java持久层API，是JDK 5.0注解或XML描述对象－关系表的映射关系，并将运行期的实体对象持久化到数据库中。

　　　Sun引入新的JPA ORM规范出于两个原因：其一，简化现有Java EE和Java SE应用开发工作；其二，Sun希望整合ORM技术，实现天下归一。

　　　JPA提供一种标准的ORM解决方案，该解决方案完全集成到EJB3.0兼容的容器中。

一、导包

(1) spring-data-jpa

(2) hibernate-entitymanager

<spring-data-jpa.version>1.11.9.RELEASE</spring-data-jpa.version>
<hibernate.version>5.2.12.Final</hibernate.version>
<!-- JPA -->
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-jpa</artifactId>
        <version>${spring-data-jpa.version}</version>
    </dependency>
    
    <dependency>
            <groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${hibernate.version}</version>
</dependency>

二、修改配置文件

(1) 把Hibernate sessionFactory 替换为entityManagerFactory

(2) 把Hibernate的TransactionManager 替换为 JpaTransactionManager

(3) 加入JPA头文件配置，并且指定JPA实现的持久层的根目录 

 

<?xml version="1.0" encoding="UTF-8"?>
<beans 
xmlns="http://www.springframework.org/schema/beans"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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/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.引入公共配置文件 db.properties-->
    <context:property-placeholder location="classpath:db.properties"/>
    <!--2.配置数据源（c3p0）-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
        <property name="driverClass" value="${dataSource.driverClassName}"></property>
        <property name="jdbcUrl"      value="${dataSource.url}"></property>
        <property name="user"          value="${dataSource.username}"></property>
        <property name="password"      value="${dataSource.password}"></property>
        <property name="maxPoolSize" value="40"></property>
        <property name="minPoolSize" value="1"></property>
        <property name="initialPoolSize" value="1"></property>
        <property name="maxIdleTime" value="20"></property> 
    </bean>
    
    <!--3.配置JPA entityManagerFactory-->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="packagesToScan" value="com.demo.entity" />
        <!-- 用于指定持久化实现厂商类 -->
        <property name="persistenceProvider">    
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider"/>
        </property>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.dialect" >${hibernate.dialect}</prop>                
                <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
                <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
                <prop key="hibernate.max_fetch_depth">2</prop>
        </property>
    </bean>
    <!--4.配置JPA事务管理-->
    <bean id="transactionManager"  class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>
    <!--5.注解事务 ：transaction-manager="transactionManager" proxy-target-class="true" -->
    <tx:annotation-driven />    
    
    <!--6.指定JPA实现的持久层的根目录 
        entity-manager-factory-ref:默认获取id=entityManagerFactory Bean
        transaction-manager-ref:默认获取id=transactionManager Bean
    -->
    <jpa:repositories base-package="com.demo.dao" />
</beans>

三、继承接口

Repository 

CrudRepository extends Repository

 

PagingAndSortingRepository  extends CrudRepository

JpaRepository  extends PagingAndSortingRepository

 

public interface UserRepository extends CrudRepository<User,Long>
{

}