java动态代理详解

public interface Subject
{
public void doSomething();
}
public class RealSubject implements Subject
{
public void doSomething()
{
System.out.println( "call doSomething()" );
}
}
public class ProxyHandler implements InvocationHandler
{
private Object proxied;

public ProxyHandler( Object proxied )
{
this.proxied = proxied;
}

public Object invoke( Object proxy, Method method, Object[] args ) throws Throwable
{
//在转调具体目标对象之前，可以执行一些功能处理

//转调具体目标对象的方法
return method.invoke( proxied, args);

//在转调具体目标对象之后，可以执行一些功能处理
}
}

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import sun.misc.ProxyGenerator;
import java.io.*;
public class DynamicProxy
{
public static void main( String args[] )
{
RealSubject real = new RealSubject();
Subject proxySubject = (Subject)Proxy.newProxyInstance(Subject.class.getClassLoader(),
new Class[]{Subject.class},
new ProxyHandler(real));

proxySubject.doSomething();

//write proxySubject class binary data to file
createProxyClassFile();
}

public static void createProxyClassFile()
{
String name = "ProxySubject";
byte[] data = ProxyGenerator.generateProxyClass( name, new Class[] { Subject.class } );
try
{
FileOutputStream out = new FileOutputStream( name + ".class" );
out.write( data );
out.close();
}
catch( Exception e )
{
e.printStackTrace();
}
}
}