动态代理模式

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import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Random;

/**
* 动态代理模式–jdk_api
* Subject将要被代理的接口
* InvocationHandler定义了对被代理对象的处理
* Proxy用来生成代理对象的工具类
* newProxyInstance在该方法中利用反射，拼接重新生
* 成新的代理类字符串，将其编译成class文件，再加载
* 再次利用反射，然后生成代理对象
* @author fantasy
*
*/

public class DynamicProxyTest {    public static void main(String[] args) {        Subject sj = new SubjectImpl();        TimeHandler handler = new TimeHandler(sj);        Subject s = (Subject)Proxy.newProxyInstance(Subject.class.getClassLoader(), new Class[]{Subject.class}, handler);        s.caculate();    }}interface Subject{    public void caculate();}class SubjectImpl implements Subject{    @Override    public void caculate() {        try {            Thread.sleep(new Random().nextInt(10000));        } catch (InterruptedException e) {            e.printStackTrace();        }    }}class TimeHandler implements InvocationHandler{    private Subject target= null;    public TimeHandler(Subject subject){        this.target = subject;    }    @Override    public Object invoke(Object proxy, Method method, Object[] args)            throws Throwable {        long start = System.currentTimeMillis();        System.out.println("开始时间："+start);        method.invoke(target, args);        long end = System.currentTimeMillis();        System.out.println("所用时间："+(end-start));        return null;    }}

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