java动态代理的实现-蒲公英云

java动态代理的实现

墨蓝 2022-07-27 11:39 323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>
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首先上一张代码结构图：

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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);
    }
}