JPA+Spring2.5+Struts2.1.8 集成(一)

1、先集成JPA+Spring

首先导入HibernateJPA的实现包，如图

2、再导入spring的jar包如下图,另外要加入数据库驱动ojdbc14.jar，这里我用的是Oracle数据库

3、创建spring配置文件beans.xml

<?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: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:component-scan base-package="com.jason"/>-->
  
  <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
      <property name="persistenceUnitName" value="jason"/>
  </bean>  

  <bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
  	<property name="entityManagerFactory" ref="entityManagerFactory"/>
  </bean>
  
  <tx:annotation-driven transaction-manager="txManager"/>
</beans>

4、连接数据库有三种方式：1.不使用数据源；2、JDBC数据源；3.dbcp连接池；4.c3p0连接池。(个人喜欢使用c3p0 哈哈)

第一种不使用数据源：在src根目录下创建META-INF文件夹并创建persistence.xml配置文件,JPA规范要求persistence.xml必须放在类路径的META-INF目录下，在应用部署的时候会被编译到WEB-INF的class目录下。

<?xml version="1.0"?>
<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="jason" transaction-type="RESOURCE_LOCAL">
      <properties>
         <property name="hibernate.dialect" value="org.hibernate.dialect.OracleDialect"/>
         <property name="hibernate.connection.driver_class" value="oracle.jdbc.driver.OracleDriver"/>
         <property name="hibernate.connection.url" value="jdbc:oracle:thin:@localhost:1521:ORCL"/>
         <property name="hibernate.connection.username" value="jason"/>
         <property name="hibernate.connection.password" value="jason"/>
         
         <property name="hibernate.max_fetch_depth" value="3"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="hibernate.show_sql" value="false"/>
	     <property name="hibernate.format_sql" value="false"/>
      </properties>
   </persistence-unit>
</persistence>

5、创建实体类Buyer.java

package com.jason.bean.user;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;

/**
 * 用户实体
 * @Type_name: Buyer 
 * @author: JASON jason8812@yahoo.cn
 */
@Entity
public class Buyer implements Serializable{
	private static final long serialVersionUID = -7273954519684644480L;
	private String username;
	private String password;
	private String email;
	
	public Buyer(){}
	public Buyer(String username){
		this.username = username;
	}
	public Buyer(String username, String password) {
		this.username = username;
		this.password = password;
	}
	public Buyer(String username, String password, String email) {
		this.username = username;
		this.password = password;
		this.email = email;
	}
	@Id
	@Column(length=18)
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	@Column(length=32,nullable=false)
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	@Column(length=45,nullable=false)
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result
				+ ((username == null) ? 0 : username.hashCode());
		return result;
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Buyer other = (Buyer) obj;
		if (username == null) {
			if (other.username != null)
				return false;
		} else if (!username.equals(other.username))
			return false;
		return true;
	}
	
}

6、创建junit测试类BuyerTest.java

package junit.test;


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

public class BuyerTest {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
		
	}
	
	@Test
	public void save(){
		 new ClassPathXmlApplicationContext("beans.xml");
	}
}

右键save方法JUnit测试，如果数据库表里生成了buyer表就说明集成成功了！

第二种JDBC数据源，在beans.xml配置，也可以配置到jdbc.properties文件中

<bean id="JDBCdatasource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
		<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
		<property name="url" value="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8"></property>
		<property name="username" value="root"></property>
		<property name="password" value="skyadmin"></property>
		<!-- 初始连接数量 -->
		<property name="initialSize" value="50"></property>
		<!-- 最大连接数量 -->
		<property name="maxActive" value="80"></property>
	</bean>

第三种dbcp连接池，使用数据源有助于应用的性能。

首先加入支持的dbcp连接池jar包commons-dbcp.jar和commons-pool.jar

在src根目录里创建jdbc.properties文件，内容如下：

driverClassName=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@localhost:1521:ORCL
username=scott
password=tiger

initialSize=1
maxActive=100
maxIdle=8
minIdle=1

然后在beans.xml里注释掉

<!--<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
	   <property name="persistenceUnitName" value="jason"/>
  </bean>-->

添加dbcp连接池配置

<!--	2、使用dbcp数据源-->
  <context:property-placeholder location="classpath:jdbc.properties"/>
  <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="${driverClassName}"></property>
    <property name="url" value="${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="dataSource" ref="dataSource"/>
		<property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml" />
		<property name="loadTimeWeaver">
		<!--该类对JPA做一些额外工作-->
	          <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver"/>
	    </property>
	</bean>

另外persistence.xml要修改如下：

<?xml version="1.0"?>
<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">
<!--  2、dbcp数据源、c3p0数据源-->
  <persistence-unit name="jason" transaction-type="RESOURCE_LOCAL">
  	<provider>org.hibernate.ejb.HibernatePersistence</provider>
  	<properties>
		<property name="hibernate.dialect" value="org.hibernate.dialect.OracleDialect"/>
  		<property name="hibernate.max_fetch_depth" value="3"/>
  		<property name="hibernate.hbm2ddl.auto" value="update"/>
  		<property name="hibernate.jdbc.fetch_size" value="18"/>
	    <property name="hibernate.jdbc.batch_size" value="10"/>
	    <property name="hibernate.show_sql" value="false"/>
	    <property name="hibernate.format_sql" value="false"/> 
  	</properties>
  </persistence-unit>
</persistence>

OK,运行JUnit测试SUCCESS!

第四种、c3p0连接池

需要加入支持的c3p0jar包c3p0-0.9.1.2.jar

在beans.xml里需要修改dbcp连接池配置如下

<!--   3、c3p0数据源-->
    <context:property-placeholder location="classpath:jdbc.properties"/>
	<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
		<property name="driverClass" value="${driverClass}"/>
		<property name="jdbcUrl" value="${jdbcUrl}"/>
		<property name="user" value="${user}"/>
		<property name="password" value="${password}"/>
		<!-- 初始化时获取的连接数，取值应在minPoolSize与maxPoolSize之间。Default: 3  -->
		<property name="initialPoolSize" value="1"/>
		<!-- 连接池中保留的最小连接数。 -->
		<property name="minPoolSize" value="1"/>	
		<!-- 连接池中保留的最大连接数。Default: 15  -->
		<property name="maxPoolSize" value="300"/>
		<!-- 最大空闲时间,60秒内未使用则连接被丢弃。若为0则永不丢弃。Default: 0  -->
		<property name="maxIdleTime" value="60"/>	
		<!-- 当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default: 3  -->
		<property name="acquireIncrement" value="5"/>	
		<!-- 每60秒检查所有连接池中的空闲连接。Default: 0  -->
		<property name="idleConnectionTestPeriod" value="60"/>
	</bean>

jdbc.properties需改为

driverClass=oracle.jdbc.driver.OracleDriver
jdbcUrl=jdbc:oracle:thin:@localhost:1521:ORCL
user=scott
password=tiger

OKay!运行JUnit，SUCCESS！