Spring AOP(Annotation)的原理模拟兑现

Spring AOP(Annotation)的原理模拟实现

模拟需要织入的行为:记录日志

package com.spring;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
//需要实现InvocationHandler接口
public class LogInterceptor implements InvocationHandler {
    //被代理对象
 private Object target;
   
    public void beforeMethod(Method m) {
     System.out.println(m.getName()+" start logger!!!!!");
    }
 public Object invoke(Object proxy, Method method, Object[] args)
   throws Throwable {
  this.beforeMethod(method);
  method.invoke(target, args);
  return null;
 }
 public Object getTarget() {
  return target;
 }
 public void setTarget(Object target) {
  this.target = target;
 }

}

测试类：

package com.test;

import java.lang.reflect.Proxy;

import com.dao.UserDao;
import com.dao.UserDaoImpl;
import com.model.User;
import com.spring.LogInterceptor;

public class InterceptorTest {

 public static void main(String[] args) {
     UserDao userDao = new UserDaoImpl();
     LogInterceptor log = new LogInterceptor();
     log.setTarget(userDao);//设置被代理对象

  //创建UserDao的代理对象
    UserDao userDaoProxy = (UserDao)Proxy.newProxyInstance(UserDao.class.getClassLoader(), new Class[]{UserDao.class}, log);
   System.out.println(userDaoProxy.getClass());//userDaoProxy是一个UserDao的代理对象
    userDaoProxy.save(new User());
    userDaoProxy.delete(new User());
 }

}