jpa-addSpring

导包

　　1.hibernate中必须的包

　　2.hibernate中c3p0的包

　　3.hibernate中jpa的包

　　4.mysql数据库驱动包

　　5.spring中必须的包

 

整合：三点特别重要

　　1.applicationContext.xml中的全部

<?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:tx="http://www.springframework.org/schema/tx"
    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-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

<!-- 1.扫描出db.properties -->
    <context:property-placeholder location="classpath:db.properties"/>
    
<!-- 扫描基于注解的bean -->
    <context:component-scan base-package="springs"></context:component-scan>
    
<!-- 配置dataSource,使用的是c3p0 -->
    <bean class="com.mchange.v2.c3p0.ComboPooledDataSource" id="dataSource">
        <property name="jdbcUrl" value="${jdbc.url}"></property>
        <property name="user" value="${jdbc.user}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="driverClass" value="${jdbc.driverClass}"></property>
    </bean>
    
<!-- 配置entityManagerFactory -->
    <bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory">
    
        <!-- 添加dataSource -->
        <property name="dataSource" ref="dataSource"></property>
        
        <!-- 扫描的包，此包为实体类的包 -->
        <property name="packagesToScan" value="entities"></property>
        
        <!-- 为jpa提供适配的类 -->
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"></bean>
        </property>
        
        <!-- 一些jpa的配置 -->
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
        
    </bean>
    
<!-- 配置jpa的事务管理器 -->
    <bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"></property>
    </bean>
    
<!-- 配置基于注解的事务 -->
    <tx:annotation-driven transaction-manager="transactionManager"/>


</beans>

　　2.dao类中特别重要的一点：要使用@PersistenceContext来获取线程同步的entityManager

package springs;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.springframework.stereotype.Repository;

import entities.XiaoYu;

@Repository
public class XiaoYuDAO {
    @PersistenceContext//加这个注解获取线程同步的manager
    private EntityManager entityManager;

    public void save(XiaoYu xiaoYu) {
        System.out.println(entityManager);
        entityManager.persist(xiaoYu);
    }
}

　　3.service中的一点：使用@Transaction来注解事务的方法，而dao中得到的entityManager只有在事务的方法中才能发送sql语句

package springs;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import entities.XiaoYu;

@Service
public class XiaoYuService {
    @Autowired
    private XiaoYuDAO dao;

    @Transactional//这句特别重要！！！！！！！！！！没有它就不能发sql
    public void saveDpuble(XiaoYu xiaoYu1, XiaoYu xiaoYu2) {//这个方法里面的是一个事务
        dao.save(xiaoYu1);
        dao.save(xiaoYu2);
    }
}