（5）设计模式：Proxy

设计模式：Proxy

静态代理
代理实现的方法：（1）继承的方式；（2）用聚合的方式；
用继承实现代理的方式，如果实现的功能增加多的话，类会无休止的增加；
加一种代理就加一层，里层记录时间，外层记录日志。。。。
用聚合实现多态更好。

package com.bjsxt.proxy;public interface Moveable {void move();}

package com.bjsxt.proxy;import java.util.Random;public class Tank implements Moveable {@Overridepublic void move() {System.out.println("Tank Moving...");try {Thread.sleep(new Random().nextInt(10000));} catch (InterruptedException e) {e.printStackTrace();}}}

package com.bjsxt.proxy;import java.lang.reflect.Method;public interface InvocationHandler {public void invoke(Object o, Method m);}

package com.bjsxt.proxy;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;public class TimeHandler implements InvocationHandler{private Object target;public TimeHandler(Object target) {super();this.target = target;}@Overridepublic void invoke(Object o, Method m) {long start = System.currentTimeMillis();System.out.println("starttime:" + start);System.out.println(o.getClass().getName());try {m.invoke(target);} catch (Exception e) {e.printStackTrace();}long end = System.currentTimeMillis();System.out.println("time:" + (end-start));}}

package com.bjsxt.proxy;import java.io.File;import java.io.FileWriter;import java.lang.reflect.Constructor;import java.lang.reflect.Method;import java.net.URL;import java.net.URLClassLoader;import javax.tools.JavaCompiler;import javax.tools.StandardJavaFileManager;import javax.tools.ToolProvider;import javax.tools.JavaCompiler.CompilationTask;public class Proxy {public static Object newProxyInstance(Class infce, InvocationHandler h) throws Exception { //JDK6 Complier API, CGLib, ASMString methodStr = "";String rt = "\r\n";Method[] methods = infce.getMethods();/*for(Method m : methods) {methodStr += "@Override" + rt +  "public void " + m.getName() + "() {" + rt + "   long start = System.currentTimeMillis();" + rt +"   System.out.println(\"starttime:\" + start);" + rt +"   t." + m.getName() + "();" + rt +"   long end = System.currentTimeMillis();" + rt +"   System.out.println(\"time:\" + (end-start));" + rt + "}";}*/for(Method m : methods) {methodStr += "@Override" + rt +  "public void " + m.getName() + "() {" + rt + "    try {" + rt + "    Method md = " + infce.getName() + ".class.getMethod(\"" + m.getName() + "\");" + rt + "    h.invoke(this, md);" + rt + "    }catch(Exception e) {e.printStackTrace();}" + rt + "}";}String src = "package com.bjsxt.proxy;" +  rt +"import java.lang.reflect.Method;" + rt +"public class $Proxy1 implements " + infce.getName() + "{" + rt +"    public $Proxy1(InvocationHandler h) {" + rt +"        this.h = h;" + rt +"    }" + rt +"    com.bjsxt.proxy.InvocationHandler h;" + rt +methodStr +"}";String fileName = "d:/src/com/bjsxt/proxy/$Proxy1.java";File f = new File(fileName);FileWriter fw = new FileWriter(f);fw.write(src);fw.flush();fw.close();//compileJavaCompiler compiler = ToolProvider.getSystemJavaCompiler();StandardJavaFileManager fileMgr = compiler.getStandardFileManager(null, null, null);Iterable units = fileMgr.getJavaFileObjects(fileName);CompilationTask t = compiler.getTask(null, fileMgr, null, null, null, units);t.call();fileMgr.close();//load into memory and create an instanceURL[] urls = new URL[] {new URL("file:/" + "d:/src/")};URLClassLoader ul = new URLClassLoader(urls);Class c = ul.loadClass("com.bjsxt.proxy.$Proxy1");System.out.println(c);Constructor ctr = c.getConstructor(InvocationHandler.class);Object m = ctr.newInstance(h);//m.move();return m;}}

package com.bjsxt.proxy;public class Client {public static void main(String[] args) throws Exception {Tank t = new Tank();InvocationHandler h = new TimeHandler(t);Moveable m = (Moveable)Proxy.newProxyInstance(Moveable.class, h);m.move();}}