实现动态代理的两种方式介绍+例子demo(JDK、CGlib)

package cn.xym.empmis.web.filter;

import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* 解决全站乱码问题
* @author Administrator
*
*/
public class CharacterEncodingFilter implements Filter{

@Override
public void init(FilterConfig filterconfig) throws ServletException {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest servletrequest,
ServletResponse servletresponse, FilterChain filterchain)
throws IOException, ServletException {

final HttpServletRequest request = (HttpServletRequest) servletrequest;
HttpServletResponse response = (HttpServletResponse) servletresponse;
request.setCharacterEncoding("UTF-8");	//只能解决Post方式提交的乱码问题，无法解决get提交的乱码

//可以用包装设计模式，也可以用动态代理技术来解决get请求的乱码问题

filterchain.doFilter((ServletRequest) Proxy.newProxyInstance(CharacterEncodingFilter.class.getClassLoader()
, request.getClass().getInterfaces()
, new InvocationHandler() {

@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
//proxy表示：动态代理对象
//method表示：需要代理的方法
//args表示需要代理方法的参数
if (!method.getName().equals("getParameter")){
return method.invoke(request, args);
}
if (!request.getMethod().equalsIgnoreCase("get")){
return method.invoke(request, args);
}
//满足要拦截处理的条件了
String value = (String) method.invoke(request,args);
if (value == null){
return null;
}
return new String(value.getBytes("iso8859-1"),"UTF-8");
}
}), response);
}
@Override
public void destroy() {
// TODO Auto-generated method stub

}

}

<?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: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/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"> 
<!-- 准备要做为目标对象（被代理对象） -->
<bean id="userServiceImpl" class="cn.cubic.aop.service.impl.UserServiceImpl" />

<!-- 配置通知对象 -->
<!-- 前置通知 -->
<bean id="myMethodBeforeAdvice" class="cn.cubic.aop.MyMethodBeforeAdvice"/>
<!-- 后置通知 -->
<bean id="myAfterReturningAdvice" class="cn.cubic.aop.MyAfterReturningAdvice" />
<!-- 环绕通知 -->
<bean id="myMethodInterceptor" class="cn.cubic.aop.MyMethodInterceptor" />
<!-- 异常通知 -->
<bean id="myThrowsAdvice" class="cn.cubic.aop.MyThrowsAdvice"/>

<!-- 引入通知 ,自定义切入点,了解即可-->
<bean id="myMethodBeforeAdviceFilter" class="org.springframework.aop.support.NameMatchMethodPointcutAdvisor">
<property name="advice" ref="myMethodBeforeAdvice"/>
<property name="mappedNames">
<list>
<value>sayHello</value>
</list>
</property>
</bean>

<!-- 配置代理对象 -->
<bean id="proxyFactoryBean" class="org.springframework.aop.framework.ProxyFactoryBean">

<!-- 指定你希望代理的目标对象 -->
<property name="target" ref="userServiceImpl" />

<!-- 指定“代理接口”的列表 -->
<property name="proxyInterfaces">
<list>
<value>cn.cubic.aop.service.IAbstractService</value>
<value>cn.cubic.aop.service.IAbstractService2</value>
</list>
</property>

<!-- 把“通知”织入代理对象 -->
<property name="interceptorNames">
<list>
<value>myMethodBeforeAdviceFilter</value>
<value>myAfterReturningAdvice</value>
<value>myMethodInterceptor</value>
<value>myThrowsAdvice</value>
</list>
</property>
</bean>

</beans>

package cn.cubic.aop.cglib;

import java.lang.reflect.Method;

import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

/**
*
* Simple to Introduction
*
* @ProjectName:  [springAop]
* @Package:      [cn.cubic.aop.cglib]
* @ClassName:    [CGLIBProxy]
* @Description:  [描述该类的功能]
* @Author:       [逍遥梦]
* @CreateDate:   [2014-3-1 下午4:47:22]
* @UpdateUser:   [逍遥梦]
* @UpdateDate:   [2014-3-1 下午4:47:22]
* @UpdateRemark: [说明本次修改内容]
* @Version:      [v1.0]
*
*/
public class CGLIBProxy implements MethodInterceptor{

private Enhancer enhancer = new Enhancer();

public Object getProxy(Class clazz){

//设置父类
enhancer.setSuperclass(clazz);
enhancer.setCallback(this);

//通过字节码技术动态创建子类实例
return enhancer.create();
}

/**
* 所有的方法都会被这个方法所拦截。该类实现了创建子类的方法与代理的方法。getProxy(SuperClass.class)方法通过入参即父类的字节码，通过扩展父类的class来创建代理对象。intercept()方法拦截所有目标类方法的调用，obj表示目标类的实例，method为目标类方法的反射对象，args为方法的动态入参，proxy为代理类实例。
*/
@Override
public Object intercept(Object obj, Method method, Object[] args,
MethodProxy methodproxy) throws Throwable {

System.out.println("cglib实现的前置代理");

//通过代理类调用父类中的方法
Object result = methodproxy.invokeSuper(obj, args);

System.out.println("cglib实现的后置代理");
return result;
}

}

package cn.cubic.aop.service.impl;

public class CGLIBUserServiceImpl {

public void sayHello(){
System.out.println("CGLIBUserServiceImpl的sayHello方法被调用！");
}

public void sayBye(){
System.out.println("CGLIBUserServiceImpl的sayHello方法被调用！");
}
}

package cn.cubic.aop.junit;

import cn.cubic.aop.cglib.CGLIBProxy;
import cn.cubic.aop.service.impl.CGLIBUserServiceImpl;

public class CGLIBTest {

/**
* @param args
*/
public static void main(String[] args) {

CGLIBProxy proxy = new CGLIBProxy();

//生成子类，创建代理类
CGLIBUserServiceImpl impl = (CGLIBUserServiceImpl)proxy.getProxy(CGLIBUserServiceImpl.class);
impl.sayHello();

}

}