1. 静态代理：

1-1. interface

public interface Hello {    public void talk();}

1-2. some impl class

public class HelloImpl implements Hello {    @Override    public void talk() {        System.out.println("hi, helloImpl.");    }}

1-3. some proxy class

public class HelloProxy implements Hello {    private Hello hello;    public HelloProxy(){        hello = new HelloImpl();    }    @Override    public void talk() {        before();        hello.talk();        after();    }    private void after() {        System.out.println("do something after talk...");            }    private void before() {        System.out.println("do something before talk...");    }    public static void main(String[] args) {        HelloProxy hProxy = new HelloProxy();        hProxy.talk();    }}

 

2. JDK动态代理

2-1 dynamic proxy class(1.0 version)

import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;public class DynamicProxy implements InvocationHandler {    private Object target;    public DynamicProxy (Object target){        this.target = target;    }    @Override    public Object invoke(Object proxy, Method method, Object[] args)            throws Throwable {        before();        Object result = method.invoke(target, args);        after();        return result;            }    private void after() {        System.out.println("after ...");    }    private void before() {        System.out.println("before....");    }}

2-2. 测试

import java.lang.reflect.Proxy;public class TestProxy {    public static void main(String[] args) {        Hello hello = new HelloImpl();        DynamicProxy dProxy = new DynamicProxy(hello);        Hello helloProxy = (Hello) Proxy.newProxyInstance(hello.getClass().getClassLoader(),                              hello.getClass().getInterfaces(),                               dProxy);        helloProxy.talk();    }}

2-3. dynamic proxy class（2.0 version）

import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;public class DynamicProxy implements InvocationHandler {    private Object target;    public DynamicProxy (Object target){        this.target = target;    }    @Override    public Object invoke(Object proxy, Method method, Object[] args)            throws Throwable {        before();        Object result = method.invoke(target, args);        after();        return result;            }    public 
     
       T getProxy(){        return (T) Proxy.newProxyInstance(target.getClass().getClassLoader(),                target.getClass().getInterfaces(),                 this);    }    private void after() {        System.out.println("after ...");    }    private void before() {        System.out.println("before....");    }}
     

2-4 Test

import java.lang.reflect.Proxy;

public class TestProxy {

    public static void main(String[] args) {

        DynamicProxy dProxy = new DynamicProxy(new HelloImpl());

        Hello helloProxy = dProxy.getProxy();

        helloProxy.talk();

    }

}

 

3 CGLIB动态代理

jdk动态代理是基于接口的， 如果一个类没有实现任何接口，这时就不管用了

3-1. CGLib代理类

cglib 提供的是方法级别的代理，也可以理解为对方法的拦截

import java.lang.reflect.Method;import net.sf.cglib.proxy.Enhancer;import net.sf.cglib.proxy.MethodInterceptor;import net.sf.cglib.proxy.MethodProxy;public class CGLibProxy implements MethodInterceptor {    @SuppressWarnings("unchecked")    public 
     
       T getProxy(Class
      
        cls){        return (T) Enhancer.create(cls, this);    }    @Override    public Object intercept(Object obj, Method method, Object[] args,            MethodProxy proxy) throws Throwable {        before();        Object result = proxy.invokeSuper(obj, args);        after();        return result;    }    private void after() {        // TODO Auto-generated method stub    }    private void before() {        // TODO Auto-generated method stub    }}
      
     

3-2. Test

这里不需要任何的接口信息

public class TestCLIib {    public static void main(String[] args) {        CGLibProxy cgLibProxy = new CGLibProxy();        HelloImpl helloProxy = cgLibProxy.getProxy(HelloImpl.class);        helloProxy.talk();    }}

需要引入asm的相关jar， 引用asm-5.1.2.jar时报错， 引用com.springsource.org.objectweb.asm-3.2.0.jar可以