Spring 集成JPA

 

Hibernate 3.2支持JPA注解，Spring集成JPA是可选的。

下面是Spring集成JPA的一个例子。

实体类MyUser，使用JPA注解实现到数据库表myUser的映射，如下所示：

package org.shirdrn.entity;

import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Transient;

@Entity
public class MyUser {

private Long id;
private String userName;
private String password;
private String gender;
private Integer age;
private Integer birthYear;
private String addr;
private String email;

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public Long getId() {
   return id;
}

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

@Column(name="userName")
public String getUserName() {
   return userName;
}

public void setUserName(String userName) {
   this.userName = userName;
}

@Column(name="password")
public String getPassword() {
   return password;
}

public void setPassword(String password) {
   this.password = password;
}

@Column(name="gender")
public String getGender() {
   return gender;
}

public void setGender(String gender) {
   this.gender = gender;
}

@Column(name="age")
public Integer getAge() {
   return age;
}

public void setAge(Integer age) {
   this.age = age;
}

@Column(name="addr")
public String getAddr() {
   return addr;
}

public void setAddr(String addr) {
   this.addr = addr;
}

@Column(name="email")
public String getEmail() {
   return email;
}

public void setEmail(String email) {
   this.email = email;
}

@Transient
public Integer getBirthYear() {
   return new Integer(2008-age);
}

public void setBirthYear(Integer age) {
   this.birthYear = new Integer(2008-age);
}
}

其中，birthYear不是数据库中的字段，使用JPA的@Transient注解，在映射的时候，会忽略掉该成员。

持久层DAO接口如下：

package org.shirdrn.dao;

import java.util.List;

import org.shirdrn.entity.MyUser;
import org.springframework.transaction.annotation.Transactional;

@Transactional
public interface MyUserDAO {
public void createMyUser(MyUser myUser);
public void deleteMyUser(MyUser myUser);
public void updateMyUser(MyUser myUser);
public List<MyUser> queryMyUser(String queryString);
public List<MyUser> queryAll();
}

这里，使用了JPA注解，声明事务。

DAO实现类，如下所示：

package org.shirdrn.dao.impl;

import java.util.List;

import org.shirdrn.dao.MyUserDAO;
import org.shirdrn.entity.MyUser;
import org.springframework.orm.jpa.support.JpaDaoSupport;

public class MyUserDAOImpl extends JpaDaoSupport implements MyUserDAO {

public void createMyUser(MyUser myUser) {
   getJpaTemplate().persist(myUser);
}

public void deleteMyUser(MyUser myUser) {
   MyUser dbMyUser = getJpaTemplate().find(MyUser.class, myUser.getId());
   getJpaTemplate().remove(dbMyUser);
}

public void updateMyUser(MyUser myUser) {
   MyUser dbMyUser = getJpaTemplate().find(MyUser.class, myUser.getId());
   if(myUser.getUserName() != null){
    dbMyUser.setUserName(myUser.getUserName());
   }
   if(myUser.getAddr() != null){
    dbMyUser.setAddr(myUser.getAddr());
   }  
   getJpaTemplate().merge(dbMyUser);
}

@SuppressWarnings("unchecked")
public List<MyUser> queryMyUser(String queryString) {
   return (List<MyUser>)getJpaTemplate().find(queryString);
}

@SuppressWarnings("unchecked")
public List<MyUser> queryAll() {
   return (List<MyUser>)getJpaTemplate().find("from MyUser");
}
}

因为继承了JpaDaoSupport，索引需要获取一个JpaTemplate来实现访问数据库，在Spring的配置文件中要注入一个org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean。

Spring的配置文件applicationContext.xml的内容如下所示：

<?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:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">

<bean id="myDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.microsoft.jdbc.sqlserver.SQLServerDriver" />
        <property name="url" value="jdbc:microsoft:sqlserver://localhost:1433;databasename=shirdrn" />
        <property name="username" value="sa" />
        <property name="password" value="111111" />
    </bean>
<bean id="myEntityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="myDataSource"/>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="showSql" value="true" />
                <property name="generateDdl" value="true" />
            </bean>
        </property>
    </bean>
    <bean id="jpaTxManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="myEntityManagerFactory"/>
        <property name="dataSource" ref="myDataSource"/>
    </bean>
    <tx:annotation-driven transaction-manager="jpaTxManager"/>
<bean id="myUserDAOImpl" class="org.shirdrn.dao.impl.MyUserDAOImpl"
   abstract="false" lazy-init="default" autowire="default"
   dependency-check="default">
   <property name="entityManagerFactory">
    <ref bean="myEntityManagerFactory" />
   </property>
</bean>
</beans>

在META-INF目录下，还要加一个persistence.xml配置文件，如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<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="HibernateJPAPU" transaction-type="RESOURCE_LOCAL">
   <provider>org.hibernate.ejb.HibernatePersistence</provider>
   <class>org.shirdrn.entity.MyUser</class>

</persistence-unit>

</persistence>

接着，对增删改查操作进行测试，如下所示：

插入记录：

package org.shirdrn.test;

import org.shirdrn.dao.MyUserDAO;
import org.shirdrn.entity.MyUser;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestCreateMyUser {

public static void main(String[] args) {
   ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
   MyUserDAO myUserDAO = (MyUserDAO)ctx.getBean("myUserDAOImpl");
   MyUser myUser = new MyUser();
   myUser.setUserName("JohnXa");
   myUser.setPassword("123456");
   myUser.setGender("男");
   myUser.setAge(new Integer(25));
   myUser.setAddr("New York");
   myUser.setEmail("john@hotmail.com");
   myUserDAO.createMyUser(myUser);
}
}

删除记录：

package org.shirdrn.test;

import org.shirdrn.dao.MyUserDAO;
import org.shirdrn.entity.MyUser;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestDeleteMyUser {
public static void main(String[] args) {
   ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
   MyUserDAO myUserDAO = (MyUserDAO)ctx.getBean("myUserDAOImpl");
   MyUser myUser = new MyUser();
   myUser.setId(new Long(29));
   myUserDAO.deleteMyUser(myUser);
}
}

修改记录：

package org.shirdrn.test;

import org.shirdrn.dao.MyUserDAO;
import org.shirdrn.entity.MyUser;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestUpdateMyUser {
public static void main(String[] args) {
   ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
   MyUserDAO myUserDAO = (MyUserDAO)ctx.getBean("myUserDAOImpl");
   MyUser myUser = new MyUser();
   myUser.setId(new Long(28));
   myUser.setAddr("北京市");
   myUserDAO.updateMyUser(myUser);
}
}

查询记录：

package org.shirdrn.test;

import java.util.List;

import org.shirdrn.dao.MyUserDAO;
import org.shirdrn.entity.MyUser;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestQueryAllMyUser {
public static void main(String[] args) {
   ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
   MyUserDAO myUserDAO = (MyUserDAO)ctx.getBean("myUserDAOImpl");
   List<MyUser> list = myUserDAO.queryMyUser("from MyUser");
   for(MyUser user : list){
    System.out.println("ID："+user.getId()+
      "|姓名："+user.getUserName()+
      "|密码："+user.getPassword()+
      "|性别："+user.getGender()+
      "|年龄："+user.getAge()+
      "|住址："+user.getAddr()+
      "|邮箱："+user.getEmail());
   }
}
}