spring 后置处理器BeanFactoryPostProcessor和BeanPostProcessor的用法...

admin · 发表于 2013-8-30 17:36:11

http://blog.csdn.net/xiao_jun_0820/article/details/7242379

主要区别就是： BeanFactoryPostProcessor可以修改BEAN的配置信息而BeanPostProcessor不能，下面举个例子说明
BEAN类：
[java] view plain copy print ?

package com.springdemo.postProcessor;
public class PostProcessorBean {
private String username;
private String password;
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
}

package com.springdemo.postProcessor;public class PostProcessorBean { private String username; private String password; public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; }}
MyBeanPostProcessor类，实现了BeanPostProcessor接口:
[java] view plain copy print ?

package com.springdemo.postProcessor;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import com.springdemo.form.LoginForm;
public class MyBeanPostProcessor implements BeanPostProcessor {
public Object postProcessAfterInitialization(Object bean, String beanName)
throws BeansException {
// TODO Auto-generated method stub
//如果是PostProcessorBean则username信息
if(bean instanceof PostProcessorBean)
{
System.out.println("PostProcessorBean Bean initialized");
PostProcessorBean pb = (PostProcessorBean)bean;
System.out.println("username:"+pb.getUsername());
}
return bean;
}
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
// TODO Auto-generated method stub
if(bean instanceof PostProcessorBean)
{
System.out.println("PostProcessorBean Bean initializing");
PostProcessorBean pb = (PostProcessorBean)bean;
System.out.println("username:"+pb.getUsername());
}
return bean;
}
}

package com.springdemo.postProcessor;import org.springframework.beans.BeansException;import org.springframework.beans.factory.config.BeanPostProcessor;import com.springdemo.form.LoginForm;public class MyBeanPostProcessor implements BeanPostProcessor { public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { // TODO Auto-generated method stub //如果是PostProcessorBean则username信息 if(bean instanceof PostProcessorBean) { System.out.println("PostProcessorBean Bean initialized"); PostProcessorBean pb = (PostProcessorBean)bean; System.out.println("username:"+pb.getUsername()); } return bean; } public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { // TODO Auto-generated method stub if(bean instanceof PostProcessorBean) { System.out.println("PostProcessorBean Bean initializing"); PostProcessorBean pb = (PostProcessorBean)bean; System.out.println("username:"+pb.getUsername()); } return bean; }}
MyBeanFactoryPostProcessor实现了BeanFactoryPostProcessor接口:
[java] view plain copy print ?

package com.springdemo.postProcessor;
import org.springframework.beans.BeansException;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
throws BeansException {
// TODO Auto-generated method stub
//BeanFactoryPostProcessor可以修改BEAN的配置信息而BeanPostProcessor不能
//我们在这里修改postProcessorBean的username注入属性
BeanDefinition bd = beanFactory.getBeanDefinition("postProcessorBean");
MutablePropertyValues pv = bd.getPropertyValues();
if(pv.contains("username"))
{
pv.addPropertyValue("username", "xiaojun");
}
}
}

package com.springdemo.postProcessor;import org.springframework.beans.BeansException;import org.springframework.beans.MutablePropertyValues;import org.springframework.beans.factory.config.BeanDefinition;import org.springframework.beans.factory.config.BeanFactoryPostProcessor;import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor { public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException { // TODO Auto-generated method stub //BeanFactoryPostProcessor可以修改BEAN的配置信息而BeanPostProcessor不能 //我们在这里修改postProcessorBean的username注入属性 BeanDefinition bd = beanFactory.getBeanDefinition("postProcessorBean"); MutablePropertyValues pv = bd.getPropertyValues(); if(pv.contains("username")) { pv.addPropertyValue("username", "xiaojun"); } }}
编写测试用例：
[java] view plain copy print ?

package com.springdemo.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.springdemo.factory.ApplicationContextFactory;
import com.springdemo.postProcessor.PostProcessorBean;
import junit.framework.TestCase;
public class BeanPostPorcessorTest extends TestCase {
private ApplicationContext context;
protected void setUp() throws Exception {
super.setUp();
String[] paths = {"classpath*:/spring/applicationContext-*.xml"};
context = new ClassPathXmlApplicationContext(paths);
}
protected void tearDown() throws Exception {
super.tearDown();
}
public void testBeanPostProcessor()
{
}
public void testBeanFactoryPostProcessor()
{
//PostProcessorBean bean =(PostProcessorBean)ServiceLocator.getService("postProcessorBean");
PostProcessorBean bean =(PostProcessorBean)context.getBean("postProcessorBean");
System.out.println("---------------testBeanFactoryPostProcessor----------------");
System.out.println("username:"+bean.getUsername());
System.out.println("password:"+bean.getPassword());
//
}
}

package com.springdemo.test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import com.springdemo.factory.ApplicationContextFactory;import com.springdemo.postProcessor.PostProcessorBean;import junit.framework.TestCase;public class BeanPostPorcessorTest extends TestCase { private ApplicationContext context; protected void setUp() throws Exception { super.setUp(); String[] paths = {"classpath*:/spring/applicationContext-*.xml"}; context = new ClassPathXmlApplicationContext(paths); } protected void tearDown() throws Exception { super.tearDown(); } public void testBeanPostProcessor() { } public void testBeanFactoryPostProcessor() { //PostProcessorBean bean =(PostProcessorBean)ServiceLocator.getService("postProcessorBean"); PostProcessorBean bean =(PostProcessorBean)context.getBean("postProcessorBean"); System.out.println("---------------testBeanFactoryPostProcessor----------------"); System.out.println("username:"+bean.getUsername()); System.out.println("password:"+bean.getPassword()); // }}
spring配置文件如下（先不启用MyBeanFactoryPostProcessor）：
[html] view plain copy print ?

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
<bean class="com.springdemo.postProcessor.MyBeanPostProcessor"></bean>
<!--我们先把BeanFactoryPostProcessor注释掉，不启用,然后查看测试输出结果
<bean class="com.springdemo.postProcessor.MyBeanFactoryPostProcessor"></bean>
-->
<bean id="postProcessorBean" class="com.springdemo.postProcessor.PostProcessorBean" >
<property name="username" value="test"></property>
<property name="password" value="test"></property>
</bean>
</beans>

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd"> <bean class="com.springdemo.postProcessor.MyBeanPostProcessor"></bean>  <bean id="postProcessorBean" class="com.springdemo.postProcessor.PostProcessorBean" > <property name="username" value="test"></property> <property name="password" value="test"></property> </bean></beans>
测试输出结果如下：
PostProcessorBean Bean initializing
username:test
PostProcessorBean Bean initialized
username:test
---------------testBeanFactoryPostProcessor----------------
username:test
password:test
然后我们取消注释启用MyBeanFactoryPostProcessor，测试结果如下：
PostProcessorBean Bean initializing
username:xiaojun
PostProcessorBean Bean initialized
username:xiaojun
---------------testBeanFactoryPostProcessor----------------
username:xiaojun
password:test
从结果可以看出：BeanFactoryPostProcessor的回调比BeanPostProcessor要早，因为BeanPostProcess中输出的username已经变成了xiaojun,而不是test.还有就是BeanFactoryPostProcessor确实有能力改变初始化BEAN的内容，您可以试试在MyBeanPostProcess中试一试set一下username看看能不能改变BEAN实例的内容(答案应该是否定的).
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spring 后置处理器BeanFactoryPostProcessor和BeanPostProcessor的用法...

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