设计模式之代理模式(2)

package cn.asto.proxy;

import java.io.FileWriter;
import java.lang.reflect.Constructor;
import java.net.URL;
import java.net.URLClassLoader;

import javax.tools.JavaCompiler;
import javax.tools.JavaCompiler.CompilationTask;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
public class Proxy {

    public static Moveable getProxyInstance() throws Exception{
        String rt ="\r\t";
        String str =
        "package cn.asto.proxy;"+ rt +

        "public class TankTimeProxy implements Moveable {"+ rt +

        "    private Moveable t;"+ rt +
            
            
        "    public TankTimeProxy(Moveable t) {"+ rt +
        "        super();"+ rt +
        "        this.t = t;"+ rt +
        "}"+ rt +

        "    @Override"+ rt +
        "    public void move() {"+ rt +
        "        long startTime = System.currentTimeMillis();"+ rt +
        "        System.out.println(\"startTime:\"+startTime);"+ rt +
        "        t.move();"+ rt +
        "        long endTime = System.currentTimeMillis();"+ rt +
        "        System.out.println(\"Time:\"+(endTime-startTime));"+ rt +

        "    }"+ rt +


        "}";
        String fileName =System.getProperty("user.dir")+"/src/cn/asto/proxy/TankTimeProxy.java";
        FileWriter fw = new FileWriter(fileName);
        fw.write(str);
        fw.flush();
        fw.close();
        //compile
        JavaCompiler 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 instance
        URL[] urls = new URL[]{(new URL("file:/"+System.getProperty("user.dir")+"/src"))};
        URLClassLoader ul = new URLClassLoader(urls);
        Class c = ul.loadClass("cn.asto.proxy.TankTimeProxy");
        System.out.println(c);
        Constructor ctr = c.getConstructor(Moveable.class);
        Moveable m = (Moveable)ctr.newInstance(new Tank());
        return m;
    }
}

package cn.asto.compiler.test;

import cn.asto.proxy.Moveable;
import cn.asto.proxy.Proxy;

public class Test1 {

    public static void main(String args[]) throws Exception{
        Moveable m = Proxy.getProxyInstance();
        m.move();
    }
}