public interface Singer {

public abstract void sing();

public abstract String s();
}

public class MySinger implements Singer {
public void sing() {
// TODO Auto-generated method stub
System.err.println("唱歌。。。。");
}
}

public class agent implements InvocationHandler{
public Object target;

//綁定
public Object bind(Object target){
this.target=target;
//必須放回Proxy
return Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), this);
}

//重新
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
Object o =null;
System.out.println("開始事務");
System.out.println("判斷權限");

o = method.invoke(target, args);//執行方法

System.out.println("結束事務");
return o;
}
}

public class Test {
public static void main(String[] args) {
//
agent a =new agent();
Singer s= (Singer) a.bind(new MySinger());
s.sing();
}
}