Spring AspectJ的使用

首先，要引入AspectJ并且在applicationContext.xml中进行配置

<?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 https://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd">
    <!--自动注册-->
    <context:component-scan base-package="com.ibuyi.free"/>
    <!--aspectj aop代理-->
    <aop:aspectj-autoproxy/>


</beans>

<dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>5.2.3.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>1.8.9</version>
    </dependency>

然后我们就可以愉快的使用了！
先梳理一下AspectJ支持的几种通知

• 前置通知 @Before
• 后置通知 @AfterReturning
• 环绕通知 @Round
• 异常通知 @AfterThrowing

作用就不介绍了我们直接开始使用实战

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;

@Aspect
//Aspectj注解,可以认为是切面
@Component("aspectj")
//注解注册bean
public class MyAspectj {
    //前置通知
    //其中execution指定需要对那个类或者那个方法进行aop代理
    @Before(value = "save()")
    public void before(){
        System.out.println("aspectj执行前置操作");
    }

    //后置通知
    //其中returning指的是原代理方法的返回值
    @AfterReturning(value = "save()",returning = "result")
    public void after(Object result){
        System.out.println("aspectj执行后置通知");
        System.out.println(result);
    }

    //环绕通知
    @Around(value = "execution(* com.ibuyi.free.spring.Product.delete (..))")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        System.out.println("环绕前置通知");
        //如果这里不执行joinPoint.proceed()方法，则会拦截原代理方法的执行
        Object obj=joinPoint.proceed();
        System.out.println("环绕后置通知");
        return obj;
    }
    //异常通知
    @AfterThrowing(value = "execution(* com.ibuyi.free.spring.Product.* (..))",throwing = "error")
    public void error(Throwable error){
        System.out.println("发生异常"+error.getMessage());
    }

    @Pointcut(value = "execution(* com.ibuyi.free.spring.Product.save(..))")
    private void save(){
        //指定save方法,这里必须是void和private类型，上面的通知可以直接调用这个切入点，就作用在save方法上了
    }
}

package com.ibuyi.free.spring;


import org.springframework.stereotype.Component;
//目标类
@Component("product")
public class Product {

    public void save(){
        System.out.println("保存操作");
    }

    public void delete(){
        System.out.println("删除操作");
    }

    public String update(){
        System.out.println("更新操作");
        return "helloworld";
    }

    public void find(){
        System.out.println("查询操作");
    }


}

package com.ibuyi.free.spring;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;
//测试类
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class iTest {
    @Resource(name = "product")
    Product product;
    @Test
    public void demo1(){
      product.save();
      
    }
}

上面是通过注解方法使用AspectJ,下面介绍如何通过xml配置使用AspectJ

<?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 https://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd">
   <!--目标类-->
    <bean id="person" class="com.ibuyi.free.spring.Person"/>
    <!--切面类-->
    <bean id="myaspectjxml" class="com.ibuyi.free.spring.MyAspectJXml"/>

    <!--配置aop-config-->
    <aop:config>
        <aop:pointcut id="point1" expression="execution(* com.ibuyi.free.spring.Person.say(..))"></aop:pointcut>
        <aop:aspect ref="myaspectjxml">
            <aop:before method="save" pointcut-ref="point1"/>
        </aop:aspect>
    </aop:config>



</beans>

package com.ibuyi.free.spring;

public class Person {
    public void say(){
        System.out.println("说话....");
    }
    public void sleep(){
        System.out.println("睡觉....");
    }
    public void eat(){
        System.out.println("吃饭....");
    }
    public void smile(){
        System.out.println("微笑....");
    }

}

package com.ibuyi.free.spring;

public class MyAspectJXml {
    public void save(){
        System.out.println("前置通知");
    }
}

结果可以自行测试！