Spring AOP基于注解的Demo

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2019-02-10

22:51:27

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Spring

,

在XML文件里配置AOP的各种切面配置比较麻烦，也可以直接通过注解来完成

首先是Pointcut，声明一个接口

package com.lihuia.aop.annotation;

/**
 * Copyright (C), 2018-2019
 * FileName: Hello
 * Author:   lihui
 * Date:     2019/2/10
 */

public interface Hello {
 
    void sayHello();
}

接口的实现类如下

package com.lihuia.aop.annotation;

/**
 * Copyright (C), 2018-2019
 * FileName: HelloImpl
 * Author:   lihui
 * Date:     2019/2/11
 */

public class HelloImpl implements Hello {
 
    @Override
    public void sayHello() {
        System.out.println("Hello World");
    }
}

使用注解，切点表达式里的sayHello()方法被调用即可触发切面

"execution(* com.lihuia.aop.annotation.Hello.sayHello(..))"

定义切面，举个例子，比如我们在sayHello()之前还不是Friends，sayHello()了之后才是Friends

具体Advice的含义如下

那么在sayHello()被调用就会触发切面，切点表达式作为参数传入Advice各个注解，具体就会执行Advice注解的方法

package com.lihuia.aop.annotation;

import org.aspectj.lang.annotation.*;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Copyright (C), 2018-2019
 * FileName: Friend
 * Author:   lihui
 * Date:     2019/2/11
 */

@Aspect
public class Friend {

    @Before("execution(* com.lihuia.aop.annotation.Hello.sayHello(..))")
    public void beforeFriends() {
        System.out.println("BeforeFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }

    @AfterReturning("execution(* com.lihuia.aop.annotation.Hello.sayHello(..))")
    public void afterReturningFriends() {
        System.out.println("AfterReturningFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }

    @After("execution(* com.lihuia.aop.annotation.Hello.sayHello(..))")
    public void afterFriends() {
        System.out.println("AfterFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }

    @AfterThrowing("execution(* com.lihuia.aop.annotation.Hello.sayHello(..))")
    public void afterThrowingTime() {
        System.out.println("AfterThrowingFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }
}

同时也可以定义一个命名切点，通过一个hello()方法来使用@Pointcut注解，这样任何切点表达式都可以直接使用hello()来标志

package com.lihuia.aop.annotation;

import org.aspectj.lang.annotation.*;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Copyright (C), 2018-2019
 * FileName: Friend
 * Author:   lihui
 * Date:     2019/2/11
 */

@Aspect
public class Friend {
    
    @Pointcut("execution(* com.lihuia.aop.annotation.Hello.sayHello(..))")
    public void hello() {
        
    }
    
    @Before("hello()")
    public void beforeFriends() {
        System.out.println("BeforeFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }

    @AfterReturning("hello()")
    public void afterReturningFriends() {
        System.out.println("AfterReturningFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }

    @After("hello()")
    public void afterFriends() {
        System.out.println("AfterFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }

    @AfterThrowing("hello()")
    public void afterThrowingTime() {
        System.out.println("AfterThrowingFriends: " +
                new SimpleDateFormat("yyyy-MM-dd-HH:mm:ss:SSS").format(new Date()));
    }
}

具体XML里配置

aop:aspectj-autoproxy元素，启用AspectJ自动代理

AspectJ自动代理会给@Aspect注解的bean创建一个代理，这个代理会围绕着所有该切面的切点所匹配的bean，如此一来，将会给bean创建一个代理，Friend类中的通知方法将会在hello()调用前后执行

<?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"
      xmlns:context="http://www.springframework.org/schema/context"
      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-4.2.xsd
      http://www.springframework.org/schema/context 
      http://www.springframework.org/schema/context/spring-context.xsd">

   <bean id="hello" class="com.lihuia.aop.annotation.HelloImpl"></bean>

   <context:component-scan base-package="com.lihuia.aop.annotation"></context:component-scan>
   <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
   <bean class="com.lihuia.aop.annotation.Friend"></bean>
</beans>

添加测试类

package com.lihuia.aop.annotation;

import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.testng.AbstractTestNGSpringContextTests;
import org.testng.annotations.Test;

import javax.annotation.Resource;

/**
 * Copyright (C), 2018-2019
 * FileName: AopTest
 * Author:   lihui
 * Date:     2019/2/11
 */

@ContextConfiguration(locations = {
        "classpath*:aopAnnotation.xml"
})
public class AopTest extends AbstractTestNGSpringContextTests {
    
    @Resource
    private Hello hello;
    
    @Test(description = "基于注解的AOP")
    public void aopTest() {
        hello.sayHello();
    }

}

运行结果

BeforeFriends: 2019-02-11-02:16:06:383
Hello World
AfterFriends: 2019-02-11-02:16:06:386
AfterReturningFriends: 2019-02-11-02:16:06:388

这样切点处通知的触发都OK

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