Spring+JPA整合

参考：Spring Recipes

 

1. 涉及内容：
  * 在Spring中配置JPA EntityManagerFactory
  * 配置注解声明式事务
  * 用JPA的上下文注入持久化对象

2. 实现步骤：

       0）.依赖包：hibernate-annotations-3.4.0.GA

                         hibernate-entitymanager-3.4.0.GA

                         spring-framework-2.5.6
       1）.编写Course实体类并添加JPA注解，代码如下：

package com.local.domain;

import java.util.Date;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="t_course")
public class Course {
	@Id
	@GeneratedValue
	private Long id;
	
	private String title;
	
	private Date beginDate;
	
	private Date endDate;
	
	private int fee;

	public long getId() {
		return id;
	}

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

	public String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}

	public Date getBeginDate() {
		return beginDate;
	}

	public void setBeginDate(Date beginDate) {
		this.beginDate = beginDate;
	}

	public Date getEndDate() {
		return endDate;
	}

	public void setEndDate(Date endDate) {
		this.endDate = endDate;
	}

	public int getFee() {
		return fee;
	}

	public void setFee(int fee) {
		this.fee = fee;
	}
}

 

      2）编写CourseDao接口和JpaCourseDao实现，代码如下：

package com.local.dao;

import com.local.domain.Course;

public interface CourseDao {
	public void save(Course course);
	public void delete(Long id);
	public Course get(Long id);
}

 

package com.local.dao.impl;

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

import org.hibernate.HibernateException;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import com.local.dao.CourseDao;
import com.local.domain.Course;

@Repository("courseDao")
public class JpaCourseDao implements CourseDao{
	
	@PersistenceContext
	private EntityManager manager;
	
	public JpaCourseDao(){
	}

	@Override
	@Transactional
	public void delete(Long id) {
			Course course=manager.find(Course.class, id);
			manager.remove(course);
	}

	@Override
	public Course get(Long id) {
			return manager.find(Course.class, id);
	}

	@Override
	@Transactional
	public void save(Course course) {
			manager.merge(course);
	}
}

 

      3）在classpath根部的META-INF目录下创建persistence.xml文件，代码如下：

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
   version="1.0">
   <persistence-unit name="course">
   <persistence-unit>
</persistence>

     4)配置spring配置文件
       (1）打开注解支持
       (2）开启组件扫描
       (3）配置数据源：
                   编辑jdbc.properties文件，配置连接属性
       (4）配置实体管理工厂
       (5）配置事务管理器，并打开注解事务
      （6）注册PersistenceExceptionTranslationPostProcessor，
                 实现JPA原生API抛出的异常到spring的DataAccessException层次结构的转换

 

       applicationContext.xml内容如下：

<?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:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd ">
	<context:annotation-config/>
	<context:component-scan base-package="com.local"/>
	<tx:annotation-driven/>
	
	<context:property-placeholder location="classpath:jdbc.properties"/>
	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
		destroy-method="close">
		<property name="driverClassName" value="${driverClassName}" />
		<property name="url" value="${url}" />
		<property name="username" value="${username}" />
		<property name="password" value="${password}" />
		<property name="initialSize" value="${initialSize}" />
		<property name="maxActive" value="${maxActive}" />
		<property name="maxIdle" value="${maxIdle}" />
		<property name="minIdle" value="${minIdle}" />
	</bean>
	
	<bean id="entityManagerFactory" 
		class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
		<property name="persistenceUnitName" value="course"/>
		<property name="dataSource" ref="dataSource"/>
		<property name="jpaVendorAdapter">
			<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
				<property name="databasePlatform" value="org.hibernate.dialect.MySQL5Dialect"></property>
				<property name="showSql" value="true"/>
				<property name="generateDdl" value="true"/>
			</bean>	
		</property>
	</bean>
	
	<bean id="transactionManager" 
		class="org.springframework.orm.jpa.JpaTransactionManager">
		<property name="entityManagerFactory" ref="entityManagerFactory"></property>
	</bean>
	<!-- 将加有Repository注解的使用JPA或者Hibernate原生API的方法所抛出的异常转化为Spring的DataAccessException中的异常 -->
	<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"></bean>
</beans>

 

 

             jdbc.properties属性文件内容如下：

driverClassName=org.gjt.mm.mysql.Driver
url=jdbc\:mysql\://localhost\:3306/db_jpa?useUnicode\=true&characterEncoding\=UTF-8
username=root
password=root
initialSize=1
maxActive=500
maxIdle=2
minIdle=1

       5）编写Junit测试：

package com.local.dao.impl;

import java.util.Date;

import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.local.dao.CourseDao;
import com.local.domain.Course;


public class CourseDaoImplTest {
	private static ApplicationContext ctx;
	private static CourseDao courseDao;
	
	@BeforeClass
	public static void init(){
		ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
		courseDao=(CourseDao)ctx.getBean("courseDao");
	}
	@Test
	public void testSave(){
		Course course=new Course();
		course.setTitle("course2");
		course.setBeginDate(new Date());
		course.setEndDate(new Date());
		course.setFee(100);
		courseDao.save(course);
	}
	
	@Test
	public void testGet(){
		Course course=courseDao.get(new Long(3));
		System.out.println("title: "+course.getTitle());
		System.out.println("beginDate: "+course.getBeginDate());
		System.out.println("endDate: "+course.getEndDate());
		System.out.println("fee: "+course.getFee());
	}
}

 

3. 其他说明：

      *1. @PersistenceContext注解：

                 给加该注解的属性注入实体管理器

      *2. @PersistenceUnit注解：

                 注入实体管理器工厂

      *3. 在Spring配置文件中加入了JPA的连接，在persistence.xml中不需配置了，否则会出现

             java.lang.UnsupportedOperationException: Not supported by BasicDataSource之类的异常