java动态代理的实现

墨蓝 2022-07-27 11:39 205阅读 0赞

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">java动态代理的实现：</span>

首先上一张代码结构图：

![Center][]

代码：

package com.test.interf;
    
    public interface UserDao {
    	
    	public int add(int x,int y);
    
    }

package com.test.impli;
    
    import com.test.interf.UserDao;
    
    public class UserDaoImpl implements UserDao {
    
    	@Override
    	public int add(int x, int y) {
    		
    		int sum = x + y;
    		
    		return sum;
    		
    	}
    
    }

package com.test.proxy;
    
    import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    import java.lang.reflect.Proxy;
    import java.util.Arrays;
    
    import com.test.interf.UserDao;
    
    public class UserProxy {
    	
    	private UserDao target;
    	
    	public UserProxy(UserDao target) {
    		super();
    		this.target = target;
    	}
    	
    	public UserDao getUserProxy() {
    		
    		UserDao proxy = null;
    		
    		ClassLoader loader = target.getClass().getClassLoader();
    		
    		Class[] interfaces = new Class[]{UserDao.class};
    		
    		InvocationHandler h = new InvocationHandler() {
    			
    			@Override
    			public Object invoke(Object proxy, Method method, Object[] args)
    					throws Throwable {
    				String methodName = method.getName();
    				System.out.println("start \\\\ methodName is:::::"+methodName + " args is::"+Arrays.toString(args));
    				
    			    Object result = null;
    			    
    			    result = method.invoke(target, args);
    			    
    			    
    			    System.out.println("end \\\\");
    				
    				return result;
    			}
    		};
    		
    		proxy = (UserDao) Proxy.newProxyInstance(loader, interfaces, h);
    		
    		return proxy;
    	}
    
    
    }

package com.test.test;
    
    import com.test.impli.UserDaoImpl;
    import com.test.interf.UserDao;
    import com.test.proxy.UserProxy;
    
    public class Main {
    
    	public static void main(String[] args) {
    		
    		UserDao ud = new UserDaoImpl();
    		
    		ud = new UserProxy(ud).getUserProxy();
    		
    		ud.add(1, 2);
    	
    	
    
    	}
    
    }

运行结果：

start \\\\ methodName is:::::add args is::\[1, 2\]  
end \\\\

[Center]: /images/20220724/d9a8ae4867f444d0941994d609e795a3.png