ServiceProxy.java

    package com.ibm.dynamicproxy;  
      
    import java.lang.reflect.InvocationHandler;  
    import java.lang.reflect.Method;  
    import java.lang.reflect.Proxy;  
      
    public class ServiceProxy implements InvocationHandler {  
      
        private Object target;  
          
        public ServiceProxy(Object target){  
            this.target = target;  
        }  
          
        @Override  
        public Object invoke(Object proxy, Method method, Object[] args)  
                throws Throwable {  
            Object result = null;  
            result = method.invoke(target, args);  
            return result;  
        }  
          
        /**
         * @param target
         * @return 返回委托類接口的實例對象
         */  
        public Object getProxyInstance(){  
            return Proxy.newProxyInstance(target.getClass().getClassLoader(),   
                    target.getClass().getInterfaces(), this);  
        }  
    }  

    package com.ibm;  
      
    import com.ibm.delegate.Service;  
    import com.ibm.delegate.ServiceImpl;  
    import com.ibm.dynamicproxy.ServiceProxy;  
      
    public class ServiceTest {  流行線
      
        /**
         * @param args
         */  
        public static void main(String[] args) {  
            //創建委托類實例，即被代理的類對象  
            ServiceImpl target = new ServiceImpl();  
            //創建動態代理類  
            ServiceProxy proxy = new ServiceProxy(target);  
            Service service = (Service) proxy.getProxyInstance();  
            String date = service.queryDate();  
            System.out.println(date);  
            int result = service.sub(10, 20);  
            System.out.println("10-20 = "+result);  
        }  
    }  

修改兩個方法，做測試：

ServiceImpl.java

    public String ownMethod(){  
        System.out.println("It's my own method");  
        return "user";  
    }  

ServiceProxy.java

    @Override  
    public Object invoke(Object proxy, Method method, Object[] args)  
            throws Throwable {  
        Object result = null;  
        if(!(target instanceof ServiceImpl)){  
            System.out.println("不能代理該對象");  
            return result;  
        }else if(!((ServiceImpl)target).ownMethod().equals("admin")){  
            System.out.println("權限不夠");  
            return result;  
        }  
        result = method.invoke(target, args);  
        return result;  
    }