Spring+JPA整合
参考：Spring Recipes
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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@GeneratedValueprivate 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{@PersistenceContextprivate EntityManager manager;public JpaCourseDao(){}@Override@Transactionalpublic void delete(Long id) {Course course=manager.find(Course.class, id);manager.remove(course);}@Overridepublic Course get(Long id) {return manager.find(Course.class, id);}@Override@Transactionalpublic 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
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?????? 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" 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" value="course"/><property name="dataSource" ref="dataSource"/><property name="jpaVendorAdapter"><bean value="org.hibernate.dialect.MySQL5Dialect"></property><property name="showSql" value="true"/><property name="generateDdl" value="true"/></bean></property></bean><bean id="transactionManager" 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 name="code">driverClassName=org.gjt.mm.mysql.Driverurl=jdbc\:mysql\://localhost\:3306/db_jpa?useUnicode\=true&characterEncoding\=UTF-8username=rootpassword=rootinitialSize=1maxActive=500maxIdle=2minIdle=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;@BeforeClasspublic static void init(){ctx=new ClassPathXmlApplicationContext("applicationContext.xml");courseDao=(CourseDao)ctx.getBean("courseDao");}@Testpublic void testSave(){Course course=new Course();course.setTitle("course2");course.setBeginDate(new Date());course.setEndDate(new Date());course.setFee(100);courseDao.save(course);}@Testpublic 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
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