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