spring学习--AOP五个通知

五个通知

​1）前置通知 ：函数执行前增强
2）后置通知 ：函数执行后增强，除非异常，最后执行
3）环绕通知 ：函数执行的前后都增强
4）异常通知 ：出现异常的时候执行
5）最终通知：不管出不出现异常，都会执行，类似于异常捕获的finally

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五个通知完全基于注解开发

• 主类编写：

package Dao;
import org.springframework.stereotype.Component;

@Component//注解  创建对象
public class UserLogin {
    public void login(){

        System.out.println("now is logining......");


    }
}

---

• 代理类编写：

package Dao;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.junit.jupiter.api.Order;
import org.springframework.stereotype.Component;

@Component//创建对象
@Aspect//切面   生成代理对象
public class UserLogin_Proxy {


    @Before(value = "execution(* Dao.UserLogin.login())")
    public void before(){
        System.out.println("在login前执行.....【前置通知】");
    }

    @After(value = "execution(* Dao.UserLogin.login())")
    public void after(){
        System.out.println("在login后执行.....但还没有返回返回值...【最终通知】");
    }

    @AfterReturning(value = "execution(* Dao.UserLogin.login())")
    public void afterReturning(){
        System.out.println("在login后执行.........在返回值之后（最后执行）...【后置通知（返回通知）】");
    }

    @Around(value = "execution(* Dao.UserLogin.login())")
    public void around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable{
        System.out.println("在login前执行........【环绕通知】");

        //被增强的方法执行   login
        proceedingJoinPoint.proceed();

        System.out.println("在login后执行........【环绕通知】");


    }

    @AfterThrowing(value = "execution(* Dao.UserLogin.login())")
    public void afterThrowing(){
        System.out.println("在login产生异常时执行........【异常通知】");
    }
}

---

• 配置类编写：

package Config_replace_xml;

import org.springframework.beans.factory.annotation.Configurable;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

@Configuration//作为配置类，代替xml文件
@ComponentScan(basePackages = {"Dao"})
@EnableAspectJAutoProxy(proxyTargetClass = true)//开启Aspect生成代理对象

public class Config_class {

}

---

• 测试类编写：

package TestPackage;

import Config_replace_xml.Config_class;
import Dao.UserLogin;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class TestDemo2 {

    @Test
    public void Testdemo2(){
        ApplicationContext context =
                new AnnotationConfigApplicationContext(Config_class.class);
        UserLogin userLogin = context.getBean("userLogin", UserLogin.class);
        System.out.println(userLogin);

        userLogin.login();
    }
}

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运行结果

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• 文件排布为：
  

配置文件基于xml编写（与上面结果等价）

• 只需要删除配置类Config_class，再添加xml配置文件即可
• xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
            <!--命名空间设定  context   aop  -->
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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 http://www.springframework.org/schema/context/spring-context.xsd
                            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">


    <!--开启注解扫描-->
    <context:component-scan base-package="Dao"></context:component-scan>
    <!--开启代理对象-->
    <aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>

---

• 测试类改写为：

package TestPackage;

import Config_replace_xml.Config_class;
import Dao.UserLogin;

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

public class TestDemo2 {

    @Test
    public void Testdemo2(){
        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");
        UserLogin userLogin = context.getBean("userLogin", UserLogin.class);
        System.out.println(userLogin);

        userLogin.login();
    }
}

测试结果等价