动态代理介绍

Person接口：

/** * Created by kaizige on 2017/8/27. */public interface Person {    public void walk();}

Person实现类：

/** * Created by kaizige on 2017/8/27. */public class PersonImpl implements Person {    public void walk() {        System.out.println("walk");    }}

动态代理类：

import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;/** * Created by kaizige on 2017/8/27. */public class DynaticProxy implements InvocationHandler {    private  Object object;    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {        before();        Object res=method.invoke(object,args);        after();        return res;    }    public DynaticProxy(Object object){        this.object=object;    }    private void before(){        System.out.println("before");    }    private void after(){        System.out.println("after");    }    public <T> T getProxy(){        return (T) Proxy.newProxyInstance(object.getClass().getClassLoader(),object.getClass().getInterfaces(),this);    }}

上面的动态代理类只能对有接口的类进行代理，若要对没有接口的类进行代理，则需要使用CGLib动态代理。

import org.springframework.cglib.proxy.Enhancer;import org.springframework.cglib.proxy.MethodInterceptor;import org.springframework.cglib.proxy.MethodProxy;import java.lang.reflect.Method;/** * Created by kaizige on 2017/8/27. */public class CGLibProxy implements MethodInterceptor {    public Object intercept(Object o, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {        before();        Object res=methodProxy.invokeSuper(o,args);        after();        return res;    }    public <T> T getProxy(Class<T> cls){        return (T) Enhancer.create(cls,this);    }    private void before(){        System.out.println("before");    }    private void after(){        System.out.println("after");    }}

测试类：

/** * Created by kaizige on 2017/8/27. */public class Main {    public static void main(String[] args) {        DynaticProxy proxy=new DynaticProxy(new PersonImpl());        Person p=proxy.getProxy();        p.walk();        CGLibProxy proxy1=new CGLibProxy();        People people=proxy1.getProxy(People.class);        people.walk();        CGLibProxy proxy2=new CGLibProxy();        Person person=proxy2.getProxy(PersonImpl.class);        person.walk();    }}