3.8、AOP操作（全注解方式，推荐）

（1）创建配置类，不需要创建 xml 配置文件

@Configuration
@ComponentScan(basePackages = {"com.atguigu"})
@EnableAspectJAutoProxy(proxyTargetClass = true)
public class ConfigAop {
}

1**、创建两个类，增强类和被增强类，创建方法
被增强类：**

package com.wzy.aspect;
import org.springframework.stereotype.Component;
@Component
public class User {
        public void user() {
            System.out.println("user方法执行啦");
        }
}

增强类：

package com.wzy.aspect;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;
//增强的类
@Component
//@Aspect
public class UserProxy {
        //抽取公共部分
    @Pointcut(value = "execution(* com.wzy.aspect.User.user(..))")
    public void pointdemo() {
    }
    //前置通知
    //@Before 注解表示作为前置通知
    @Before(value = "pointdemo()")
    public void before() {
        System.out.println("1、before.........");
    }
    //后置通知（返回通知）
    @AfterReturning(value = "pointdemo()")
    public void afterReturning() {
        System.out.println("2、afterReturning.........在方法返回值后执行");
    }
    //最终通知
    @After(value = "pointdemo()")
    public void after() {
        System.out.println("3、after.........在方法后执行");
    }
    //异常通知
    @AfterThrowing(value = "pointdemo()")
    public void afterThrowing() {
        System.out.println("4、afterThrowing.........");
    }
    //环绕通知
    @Around(value = "pointdemo()")
    public void around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        System.out.println("环绕之前.........");
        //被增强的方法执行
        Object proceed = proceedingJoinPoint.proceed();
        System.out.println("环绕之后.........");
    }
}

<?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: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.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">
    <!-- 开启注解扫描,创建对象 -->
    <context:component-scan base-package="com.wzy.aspect"></context:component-scan>
    <!--创建对象,方式二--> 
<!--    <bean id="user" class="com.wzy.aspect.User"/>
    <bean id="userProxy" class="com.wzy.aspect.UserProxy"/>-->
<aop:config>
   <!-- 切入点：对哪个类的那个方法增强-->
    <aop:pointcut id="u" expression="execution(* com.wzy.aspect.User.user())"/>
  <!-- ref：增强类对象 的bean的id -->
    <aop:aspect ref="userProxy">
      <!-- 
            method="before"：前置通知 
            pointcut-ref="u"：引入要切入的点
      -->
        <aop:before method="before" pointcut-ref="u"/>
    </aop:aspect>
</aop:config>
</beans>

测试：

package com.wzy.aspect;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestAspect {
    ApplicationContext applicationContext =
            new ClassPathXmlApplicationContext("com/wzy/aspect/bean.xml");
    @Test
    public void test1() {
        User user = applicationContext.getBean("user", User.class);
        user.user();
    }
}

输出结果：

1、before……… user方法执行啦