1 1.代理接口：Moveable.java
  2
  3 package com.test;
  4
  5 public interface Moveable {
  6
  7        void move();
  8
  9 }
 10
 11
 12 2.被代理对象：Tank.java
 13 package com.test;
 14
 15 import java.util.Random;
 16
 17 public class Tank implements Moveable {
 18
 19     public void move() {
 20          System.out.println("Tank moving...");
 21          try {
 22              Thread.sleep(new Random().nextInt(10000));
 23          } catch (InterruptedException e) {
 24              e.printStackTrace();
 25          }
 26      }
 27
 28 }
 29
 30 3.为被代理对象产生一个代理类对象，其中是想增加记录运行时间的功能
 31
 32 package com.test;
 33
 34 import java.io.File;
 35 import java.io.FileWriter;
 36 import java.lang.reflect.Constructor;
 37 import java.lang.reflect.Method;
 38
 39 import javax.tools.JavaCompiler;
 40 import javax.tools.StandardJavaFileManager;
 41 import javax.tools.ToolProvider;
 42 import javax.tools.JavaCompiler.CompilationTask;
 43
 44 public class Proxy {
 45      public static Object newProxyInstance(Class interfaces,InvocationHandler h)throws Exception{
 46          StringBuffer methodStr = new StringBuffer();
 47          String tr = "\r\n";
 48          Method[] methods = interfaces.getMethods();
 49          //拼接代理类的方法
 50          for (Method method : methods) {
 51              methodStr.append(
 52              "    public "+ method.getReturnType()+ " " +method.getName()+"() {" + tr +
 53              "        try {" + tr +
 54              "            java.lang.reflect.Method md = " + interfaces.getName() + "." + "class.getMethod(\""  + method.getName() + "\");" + tr +
 55              "            h.invoke(this,md);" + tr +
 56              "        }catch(Exception e) {e.printStackTrace();}" + tr +
 57              "    }" + tr
 58              );
 59          }
 60
 61          //拼接代理类
 62          String src = "package com.test;" + tr +
 63          "import com.test.Moveable;" + tr +
 64          "public class TimeProxy implements " + interfaces.getName() + " {" + tr +
 65          "    private com.test.InvocationHandler h;" + tr +
 66          "    public TimeProxy(com.test.InvocationHandler h) {" + tr +
 67          "        this.h = h;" + tr +
 68          "    }" + tr +
 69          methodStr.toString() + tr +
 70          "}";
 71          //创建代理类
 72          String fileName = System.getProperty("user.dir") + "/src/com/test/TimeProxy.java";
 73          File file = new File(fileName);
 74          FileWriter writer = new FileWriter(file);
 75          writer.write(src);
 76          writer.flush();
 77          writer.close();
 78          //编译
 79          JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
 80          StandardJavaFileManager fileMgr = compiler.getStandardFileManager(null, null, null);
 81          Iterable units = fileMgr.getJavaFileObjects(fileName);
 82          CompilationTask ct = compiler.getTask(null, fileMgr, null, null, null, units);
 83          ct.call();
 84          fileMgr.close();
 85          //加载类到内存：
 86          Class c = ClassLoader.getSystemClassLoader().loadClass("com.test.TimeProxy");
 87          Constructor constructor = c.getConstructor(InvocationHandler.class); //得到参数为InvocationHandler类型的构造方法
 88          Object m = constructor.newInstance(h); //通过该构造方法得到实例
 89          return m;
 90
 91      }
 92 }
 93
 94 4.TankProxy.java
 95
 96 package com.test;
 97
 98 import java.lang.reflect.Method;
 99
100 public class TankProxy {
101      public static <T> T getBean(final Object tank) throws Exception{
102          return (T)Proxy.newProxyInstance(tank.getClass().getInterfaces()[0], new InvocationHandler(){
103              public void invoke(Object proxy, Method method) {
104                  long start = System.currentTimeMillis();
105                  System.out.println("start:"+start);
106                  try {
107                      method.invoke(tank, new Object[]{});
108                  } catch (Exception e) {
109                      e.printStackTrace();
110                  }
111                  long end = System.currentTimeMillis();
112                  System.out.println("end:"+end);
113                  System.out.println("time:"+(end-start));
114              }
115
116          });
117      }
118 }
119
120 5.测试程序：
121
122 package com.test;
123
124 import java.util.List;
125
126 import com.extend.Tank2;
127 import com.extend.Tank3;
128 import com.juhe.LogProxy;
129 import com.juhe.TimeProxy;
130
131 public class Test {
132      public static void main(String[] args) throws Exception {
133          Tank tank = new Tank();
134          Moveable m =  TankProxy.getBean(tank);
135          m.move();
136
137      }
138
139 }
140
141
142
143 执行该程序的结果为：
144 start:1369121253400
145 Tank moving...
146 end:1369121260078
147 time:6678
148
149
150
151 动态生成的代理类的内容如下：
152
153 package com.test;
154 import com.test.Moveable;
155 public class TimeProxy implements com.test.Moveable {
156      private com.test.InvocationHandler h;
157      public TimeProxy(com.test.InvocationHandler h) {
158          this.h = h;
159      }
160      public void move() {
161          try {
162              java.lang.reflect.Method md = com.test.Moveable.class.getMethod("move");
163              h.invoke(this,md);
164          }catch(Exception e) {e.printStackTrace();}
165      }
166
167 }