动态代理

1 package proxy.myproxy.dynamicProxy;
2 
3 public interface UserDao {
4     void save();
5 }

1 package proxy.myproxy.dynamicProxy;
2 
3 public class UserDaoImpl implements UserDao {
4 
5     public void save() {
6         System.out.println("UserDao save()");
7     }
8 
9 }

 1 package proxy.myproxy.dynamicProxy;
 2 
 3 import java.lang.reflect.InvocationHandler;
 4 import java.lang.reflect.Method;
 5 
 6 public class InvocationHandlerImpl implements InvocationHandler {
 7     
 8     private Object target;
 9     
10     public InvocationHandlerImpl(Object target){
11         this.target = target;
12     }
13     
14     public Object invoke(Object proxy, Method method, Object[] args)//args是那个你执行的那个方法的参数
15             throws Throwable {
　　        System.out.println(proxy.getClass());//这里输出:class $Proxy0,可以看出proxy是什么
           System.out.println(target.getClass());//这里输出:class proxy.myproxy.dynamicProxy.UserDaoImpl,可以看出target是什么
16         System.out.println("开始记录日志");
17         Object obj = method.invoke(target, args);//obj是方法执行完之后的返回值
18         System.out.println("结束记录日志");
19         return obj;
20     }
21 }

 1 package proxy.myproxy.dynamicProxy;
 2 
 3 import java.lang.reflect.Proxy;
 4 
 5 public class Test {
 6     public static void main(String[] args) {
 7         UserDao userDao = new UserDaoImpl();
 8         
 9         UserDao userDaoProxy = (UserDao) Proxy.newProxyInstance(userDao.getClass().getClassLoader(), userDao.getClass().getInterfaces(), new InvocationHandlerImpl(userDao));
10         
11         userDaoProxy.save();
12         
13     }
14 }

 

 

 

静态代理代码如下:

1 package proxy.myproxy.staticProxy;
2 
3 public interface UserDao {
4     void save();
5 }

1 package proxy.myproxy.staticProxy;
2 
3 public class UserDaoImpl implements UserDao {
4 
5     public void save() {
6         System.out.println("UserDao save()");
7     }
8 
9 }

 1 package proxy.myproxy.staticProxy;
 2 
 3 public class UserDaoImplProxy implements UserDao {
 4     
 5     private UserDao userDao = new UserDaoImpl();//合成   也可以传个引用过来
 6     
 7     
 8     
 9     public void save() {
10         
11         System.out.println("开始记录日志。。。");
12         
13         userDao.save();
14         
15         System.out.println("结束记录日志。。。。");
16         
17     }
18 
19 }

 1 package proxy.myproxy.staticProxy;
 2 
 3 public class Test {
 4     public static void main(String[] args) {
 5         UserDao userDao =  new UserDaoImplProxy();
 6         
 7         userDao.save();
 8         
 9     }
10 }