interface Subject {public String request(int[] array);public void anotherRequest();
}

public class RealSubject implements Subject {@Overridepublic String request(int[] array) {System.out.println("real do something");for(int at:array) {System.out.print(at+" ");}System.out.println();return "";}@Overridepublic void anotherRequest() {System.out.println("anotherRequest");}public void ownMethod() {System.out.println("ownMethod");}}

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;public class SubjectHandler implements InvocationHandler{private Subject subject;public SubjectHandler(Subject _subject) {subject = _subject;}@Overridepublic Object invoke(Object proxy, Method method, Object[] args)throws Throwable {System.out.println("预处理...权限校验");Object obj = method.invoke(subject, args);System.out.println("后处理...数据校验");return obj;}}

public static void main(String[] args) {Subject subject = new RealSubject();InvocationHandler handler = new SubjectHandler(subject);ClassLoader cl = subject.getClass().getClassLoader();/** Returns an instance of a proxy class for the specified interfaces * that dispatches method invocations to the specified invocation handler.* 传入的是Subject接口的所有方法*/Subject proxy = (Subject) Proxy.newProxyInstance(cl, subject.getClass().getInterfaces(), handler);//调用其中一个方法，有传入参数和返回参数int[] array = {1,2,3};String a =proxy.request(array);System.out.println(a);//调用另外一个方法
        proxy.anotherRequest();/*** 用了代理和反射实现了上下文切入！* 不需要显式创建代理类即实现代理功能，而且不仅仅代理Subject，* 在handler中读取持久化数据即可实现动态代理，而且invoke上下处理，还可以实现动态切入的效果，这也是AOP编程概念*/}

预处理...权限校验
real do something
1 2 3
后处理...数据校验预处理...权限校验
anotherRequest
后处理...数据校验