java 中动态代理详解及实例

package test; 
 
public interface Subject 
{ 
 public void doSomething(); 
} 

package test; 
public class RealSubject implements Subject{ 
 public void doSomething() { 
 System.out.println( "call doSomething()" ); 
 } 
} 

package test; 
public class SubjectProxy implements Subject { 
 Subject subimpl = new RealSubject(); 
 public void doSomething() { 
 subimpl.doSomething(); 
 } 
} 

package test; 
public class TestProxy { 
 public static void main(String args[]) { 
 Subject sub = new SubjectProxy();  
 sub.doSomething(); 
 } 
} 

package test; 
 
public interface Subject 
{ 
 public void doSomething(); 
} 

package test; 
public class RealSubject implements Subject { 
 public void doSomething() { 
 System.out.println( "call doSomething()" ); 
 } 
} 

package test; 
import java.lang.reflect.InvocationHandler; 
import java.lang.reflect.Method; 
import java.lang.reflect.Proxy; 
public class ProxyHandler implements InvocationHandler { 
 private Object tar; //绑定委托对象，并返回代理类 
 public Object bind(Object tar) { 
 this.tar = tar; //绑定该类实现的所有接口，取得代理类 
 return Proxy.newProxyInstance(tar.getClass().getClassLoader(), tar.getClass().getInterfaces(), this); 
 } 
 public Object invoke(Object proxy , Method method , Object[] args)throws Throwable { 
 Object result = null; 
 //这里就可以进行所谓的AOP编程了 
 //在调用具体函数方法前，执行功能处理 
 result = method.invoke(tar,args); 
 //在调用具体函数方法后，执行功能处理 
 return result; 
 } 
} 

public class TestProxy { 
public static void main(String args[]) { 
 ProxyHandler proxy = new ProxyHandler(); //绑定该类实现的所有接口 
 Subject sub = (Subject) proxy.bind(new RealSubject()); 
 sub.doSomething(); 
 } 
}