详解Spring工厂是如何获取Aop中的代理对象的

今天药忘吃喽~ 2024-05-24 12:50 53阅读 0赞

![dc32023b13374a8d8ee9da511eecd900.png][]

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## 一：Spring工厂对于代理的加工 ##

动态代理是通过spring工厂创建并获取代理对象的，这就解释了spring如何是将通过id的值获取的事代理的对象。我们直接看代码

package com.spring.factory;
    
    import com.spring.proxy.User;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    /**
     * @Auther: DaShu
     * @Date: 2021/6/28 21:34
     * @Description:
     */
    public class Test {
        public static void main(String[] args) {
            ApplicationContext ctx = new ClassPathXmlApplicationContext("/applicationContext2.xml");
            UserService userService = (UserService)ctx.getBean("userService");
    
            userService.login("suns","liming");
            userService.register(new User());
            //------------new Log()----------------
            //UserServiceImpl.login
            //------------new Log()----------------
            //UserServiceImpl.register
        }
    }

package com.spring.factory;
    
    import com.spring.annotation.Log;
    import org.springframework.beans.BeansException;
    import org.springframework.beans.factory.config.BeanPostProcessor;
    
    import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    import java.lang.reflect.Proxy;
    
    /**
     * @Auther: DaShu
     * @Date: 2021/6/28 21:24
     * @Description:
     */
    public class ProxyBeanPostProcessor implements BeanPostProcessor {
        @Override
        public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
            return bean;
        }
    
        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
            InvocationHandler handler = new InvocationHandler() {
                @Override
                public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                    System.out.println("------------new Log()----------------");
                    Object invoke = method.invoke(bean, args);
                    return invoke;
                }
            };
            //这样返回的已经不再是原始对象而是，加工之后产生的代理对象。
            return Proxy.newProxyInstance(ProxyBeanPostProcessor.class.getClassLoader(),bean.getClass().getInterfaces(),handler);
        }
    }

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:aop="http://www.springframework.org/schema/aop"
           xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd">
    
        <bean id="userService" class = "com.spring.factory.UserServiceImpl"/>
        <bean id = "proxyBeanPostProcessor" class = "com.spring.factory.ProxyBeanPostProcessor"/>
    </beans>

[dc32023b13374a8d8ee9da511eecd900.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/05/24/67f08eb94c9a4b10ad390ce6bb91105e.png