SpringAop--切面实例

忘是亡心i 2022-06-09 04:24 215阅读 0赞

![这里写图片描述][SouthEast]

切点：  
 execution ( \* cn.com.susq.concert.Performance.perform (..) )  
execution ： 方法执行时触发  
 \* ： 返回任意类型  
cn.com.susq.concert.Performance.perform() 全限定类路径的方法名  
(..) : 表示参数任意

## demo: ##

定义需要被通知的方法  
 SpringAop在应用运行期织入切面，AOP容器会为目标对象动态的创建一个代理对象。因此，Spring对AOP的支持仅限于方法拦截。

package cn.com.susq.concert;
    
    public interface Performance { 
        public void perform();
    }

实现接口

import org.springframework.stereotype.Component;
    
    /** * Created by susq on 2017-8-27. */
    public class PerformanceImpl implements Performance { 
        public void perform() {
            System.out.println("被通知的方法执行");
        }
    }

定义切面

package cn.com.susq.concert;
    
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.annotation.Pointcut;
    /** * Created by susq on 2017-8-27. */
    @Aspect
    public class Audience { 
    
        @Pointcut("execution(* cn.com.susq.concert.Performance.perform(..))")
        public void performance() {}
    
        @Before("performance()")
        public void silenceCellPhones() {
            System.out.println("Silencing cellPhones");
        }
        //@After, @AfterReturning, @AfterThrowing 类似
    
        @Around("performance()")
        public void watchPerformance(ProceedingJoinPoint jp) {
            try {
                System.out.println("Silencing cell phones");
                System.out.println("Taking seat");
                jp.proceed();
                System.out.println("Clap");
            } catch (Throwable e) {
                System.out.println("Demanding a refund");
            }
        }
    }

aspectj.xml 配置启用AspectJ 自动代理

<?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: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/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
    
        <aop:aspectj-autoproxy /> 
    
        <bean id="audience" class="cn.com.susq.concert.Audience"/>
        <bean id="performance" class="cn.com.susq.concert.PerformanceImpl"/>
    </beans>

单元测试类

package cn.com.susq.concert;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    /** * Created by susq on 2017-8-27. */
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration("classpath:aspectj.xml")
    public class AudienceTest { 
    
        @Autowired
        private Performance performance;
    
        @Test
        public void testPerformance() {
            performance.perform();
        }
    }

控制台输出

Silencing cell phones
    Taking seat
    Silencing cellPhones
    被通知的方法执行
    Clap

[SouthEast]: /images/20220609/a7f4a0eab3df4ed8884bcfb21bef53cd.png