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Spring-Aop核心技术

news 2025/7/21 1:21:21

前言

spring一直以来都是我们Java开发中最核心的一个技术，其中又以ioc和aop为主要技术，本篇文章主要讲一下aop的核心技术，也就是ProxyFactory技术的使用，而基本的jdk动态代理和cglib代理技术并不涉及，如有需要，请自行寻找资料

背景

package com.zxc.boot.proxy;public class OrderService {public void create() {System.out.println("创建订单");}public void payOrder() {System.out.println("支付订单");}
}

假设你有如上的对象，需要对两个方法前面都插入生成订单号的逻辑，如果是传统的方式就可以直接加入，但是过于麻烦，如果使用spring的话，就可以借助如下的工具类，如

ProxyFactory

package com.zxc.boot.proxy;import org.springframework.aop.MethodBeforeAdvice;
import org.springframework.aop.framework.ProxyFactory;import java.lang.reflect.Method;public class Main {public static void main(String[] args) {//被代理对象OrderService orderService = new OrderService();ProxyFactory proxyFactory = new ProxyFactory();//设置代理对象proxyFactory.setTarget(orderService);//添加代理逻辑proxyFactory.addAdvice(new MethodBeforeAdvice() {@Overridepublic void before(Method method, Object[] objects, Object o) throws Throwable {System.out.println("-----生成订单号------");}});//获取代理对象OrderService orderServiceProxy = (OrderService) proxyFactory.getProxy();orderServiceProxy.create();orderServiceProxy.payOrder();}
}

生成的结果如下(注：这里没有接口，肯定是使用cglib生成的代理对象)

是不是很简单呢，底层逻辑都是spring帮我们实现的，而MethodBeforeAdvice就是进行的代理逻辑，它的父接口是

Advice

这个简单理解就是对象被代理的逻辑，主要有以下的实现，如

MethodBeforeAdvice、AfterReturningAdvice、MethodInterceptor等等见名思义

但是这里有一个问题，我们两个方法都被进行了代理，那么是否有办法实现只代理某个方法，而某些方法不进行代理呢，答案是有的，代码如下

package com.zxc.boot.proxy;import org.aopalliance.aop.Advice;
import org.springframework.aop.MethodBeforeAdvice;
import org.springframework.aop.Pointcut;
import org.springframework.aop.PointcutAdvisor;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.aop.support.StaticMethodMatcherPointcut;import java.lang.reflect.Method;public class Main2 {public static void main(String[] args) {//被代理对象OrderService orderService = new OrderService();ProxyFactory proxyFactory = new ProxyFactory();//设置代理对象proxyFactory.setTarget(orderService);//添加代理逻辑proxyFactory.addAdvisor(new PointcutAdvisor() {@Overridepublic Pointcut getPointcut() {//哪些方法进行代理return new StaticMethodMatcherPointcut() {@Overridepublic boolean matches(Method method, Class<?> aClass) {//方法名为create进行代理return method.getName().equals("create");}};}//代理逻辑@Overridepublic Advice getAdvice() {return new MethodBeforeAdvice() {@Overridepublic void before(Method method, Object[] objects, Object o) throws Throwable {System.out.println("-----创建订单-----");}};}@Overridepublic boolean isPerInstance() {return false;}});//获取代理对象OrderService orderServiceProxy = (OrderService) proxyFactory.getProxy();orderServiceProxy.create();orderServiceProxy.payOrder();}
}

可以看到，只有创建订单的方法才会添加代理逻辑，而支付订单并不会加入这段逻辑，而核心的功能点就是依赖于Pointcut对象

Pointcut

Pointcut简单理解就是切掉，也就是用于判断要在哪些方法或者哪些类注入代理逻辑用的

Advisor

而Advisor简单理解就是Advice和Pointcut的组合，spring当中进行代理的逻辑也是用Advisor为维度进行处理的

以上，就是使用ProxyFactory进行代理逻辑的spring工具类，但是很明显这样使用相对来说还是比较麻烦的，所以spring提供了简易的方式让我们使用这种逻辑，如下

Spring提供的代理支持

ProxyFactoryBean

package com.zxc.boot.proxy;import org.springframework.aop.MethodBeforeAdvice;
import org.springframework.aop.framework.ProxyFactoryBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;import java.lang.reflect.Method;@Configuration
@ComponentScan("com.zxc.boot.proxy")
public class AppConfig {@Beanpublic ProxyFactoryBean proxyFactoryBean() {ProxyFactoryBean proxyFactoryBean = new ProxyFactoryBean();proxyFactoryBean.setTarget(new OrderService());proxyFactoryBean.addAdvice(new MethodBeforeAdvice() {@Overridepublic void before(Method method, Object[] objects, Object o) throws Throwable {System.out.println("-------创建订单-------");}});return proxyFactoryBean;}
}

package com.zxc.boot.proxy;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class SpringApplication {public static void main(String[] args) {ApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig.class);OrderService orderService = applicationContext.getBean(OrderService.class);orderService.create();orderService.payOrder();}
}

只要进行如上的配置，就可以识别到了，这种方式其实跟原有的差不多，只不过spring帮我们处理了最终会返回对应的代理bean回去，但是还有更简单的方式，如下

DefaultPointcutAdvisor

package com.zxc.boot.proxy;import org.springframework.aop.MethodBeforeAdvice;
import org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator;
import org.springframework.aop.support.DefaultPointcutAdvisor;
import org.springframework.aop.support.NameMatchMethodPointcut;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;import java.lang.reflect.Method;@Configuration
@ComponentScan("com.zxc.boot.proxy")
public class AppConfig2 {@Beanpublic OrderService orderService() {return new OrderService();}@Beanpublic DefaultPointcutAdvisor defaultPointcutAdvisor() {//方法名称蓝机器NameMatchMethodPointcut nameMatchMethodPointcut = new NameMatchMethodPointcut();nameMatchMethodPointcut.addMethodName("create");//设置拦截和代理逻辑DefaultPointcutAdvisor defaultPointcutAdvisor = new DefaultPointcutAdvisor();defaultPointcutAdvisor.setPointcut(nameMatchMethodPointcut);defaultPointcutAdvisor.setAdvice(new MethodBeforeAdvice() {@Overridepublic void before(Method method, Object[] args, Object target) throws Throwable {System.out.println("-------创建订单------");}});return defaultPointcutAdvisor;}//核心类，一个BeanPostProccess后置处理器，用于把扫描到的Advisor进行代理@Beanpublic DefaultAdvisorAutoProxyCreator defaultAdvisorAutoProxyCreator() {return new DefaultAdvisorAutoProxyCreator();}
}

package com.zxc.boot.proxy;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class SpringApplication {public static void main(String[] args) {ApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig2.class);OrderService orderService = applicationContext.getBean(OrderService.class);orderService.create();orderService.payOrder();}
}

不用我们多做其他处理，就可以对ioc容器中方法有create的类进行代理，你可以再添加一个类，如下

package com.zxc.boot.proxy;public class UserService {public void create() {System.out.println("用户service哦哦哦");}
}

package com.zxc.boot.proxy;import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class SpringApplication {public static void main(String[] args) {ApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig2.class);OrderService orderService = applicationContext.getBean(OrderService.class);orderService.create();orderService.payOrder();UserService userService = applicationContext.getBean(UserService.class);userService.create();}
}

这样的方式就方便多了

优化处理

其实DefaultAdvisorAutoProxyCreator只是需要导入到ioc容器中，所以配置类可以使用import进行处理，效果是一样的，如下

package com.zxc.boot.proxy;import org.springframework.aop.MethodBeforeAdvice;
import org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator;
import org.springframework.aop.support.DefaultPointcutAdvisor;
import org.springframework.aop.support.NameMatchMethodPointcut;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;import java.lang.reflect.Method;@Configuration
@ComponentScan("com.zxc.boot.proxy")
@Import(DefaultAdvisorAutoProxyCreator.class)
public class AppConfig2 {@Beanpublic UserService userService() {return new UserService();}@Beanpublic OrderService orderService() {return new OrderService();}@Beanpublic DefaultPointcutAdvisor defaultPointcutAdvisor() {//方法名称蓝机器NameMatchMethodPointcut nameMatchMethodPointcut = new NameMatchMethodPointcut();nameMatchMethodPointcut.addMethodName("create");//设置拦截和代理逻辑DefaultPointcutAdvisor defaultPointcutAdvisor = new DefaultPointcutAdvisor();defaultPointcutAdvisor.setPointcut(nameMatchMethodPointcut);defaultPointcutAdvisor.setAdvice(new MethodBeforeAdvice() {@Overridepublic void before(Method method, Object[] args, Object target) throws Throwable {System.out.println("-------创建订单------");}});return defaultPointcutAdvisor;}//    //核心类，一个BeanPostProccess后置处理器，用于把扫描到的Advisor进行代理
//    @Bean
//    public DefaultAdvisorAutoProxyCreator defaultAdvisorAutoProxyCreator() {
//        return new DefaultAdvisorAutoProxyCreator();
//    }
}

如果你不导入DefaultAdvisorAutoProxyCreator对象，那么代理逻辑就不会生效，本质就是DefaultAdvisorAutoProxyCreator类就是一个BeanPostProcessor处理器，它会针对所有类进行判断然后处理