Spring AOP demo 和获取被CGLIB代理的对象

Posted 2021-01-06 toseemydream

本文分为两部分：1）给出Spring AOP的一个例子（会使用CGLIB代理）；2）给出获取被CGLIB代理的原始对象。

1、Spring AOP Demo

这部分参考了博文（http://www.voidcn.com/blog/daguanjia11/article/p-4628090.html）

1.1添加maven依赖

 

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>4.0.5.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>4.0.5.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>4.0.5.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>4.0.5.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.8.1</version>
</dependency>

 

 

1.2添加测试类

    

public class SpringAopTest {
 
    public static class Car {
        public void go() {
            System.out.println("go go go!");
        }
    }
 
    public static class CarLogger {
 
        public void beforeRun() {
            System.out.println("car is going to run");
        }
 
        public void afterRun() {
            System.out.println("car is running");
        }
    }
 
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-aop-test.xml");
        Car car = (Car) context.getBean("car");
        System.out.println(car.getClass());
        car.go();
    }
}

 

1.3添加spring配置文件

放置在classpath的根目录下，额，放在resources目录下也就行了。

 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd">
 
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" 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-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd" >
        <bean id="car" class="com.SpringAopTest.Car"/>
        <bean id="logger" class="com.SpringAopTest.CarLogger" />
        <aop:config>
            <aop:aspect ref="logger">
                <aop:pointcut expression="execution(* com.SpringAopTest.Car.go(..))" id="go"/>
 
                <aop:before pointcut-ref="go" method="beforeRun" />
                <aop:after pointcut-ref="go" method="afterRun" />
            </aop:aspect>
        </aop:config>
    </beans>
 
</beans>

 

1.4运行main函数

得到如下结果：

     

car is going to run
go go go!
car is running

 

 

呐，你看go go go!前后都有后添加的动作吧。

 

2、获取被CGLIB代理的对象

这部分内容参考了博文（http://blog.csdn.net/liufeng520/article/details/43563161）

我们先通过debug看一下被代理对象被藏在哪里了

 

好，看完了，我们来写一下代码，如下：

import java.lang.reflect.Field;
 
import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.support.AopUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
/**
 * Created by qm on 17/2/15.
 */
public class SpringAopTest {
 
    public static class Car {
        public void go() {
            System.out.println("go go go!");
        }
    }
 
    public static class CarLogger {
 
        public void beforeRun() {
            System.out.println("car is going to run");
        }
 
        public void afterRun() {
            System.out.println("car is running");
        }
    }
 
    public static Object getTarget(Object beanInstance) {
        if (!AopUtils.isAopProxy(beanInstance)) {
            return beanInstance;
        } else if (AopUtils.isCglibProxy(beanInstance)) {
            try {
                Field h = beanInstance.getClass().getDeclaredField("CGLIB$CALLBACK_0");
                h.setAccessible(true);
                Object dynamicAdvisedInterceptor = h.get(beanInstance);
 
                Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
                advised.setAccessible(true);
 
                Object target = ((AdvisedSupport) advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();
                return target;
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            }
 
        }
        return null;
 
    }
 
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring-aop-test.xml");
        Car car = (Car) context.getBean("car");
        Object target = getTarget(car);
        System.out.println(target == car);
        System.out.println(car.getClass());
        System.out.println(target.getClass());
        car.go();
    }
}