spring 入门实战（五） aop基于注解的使用

朴灿烈づ我的快乐病毒、 2022-05-28 00:45 169阅读 0赞

### 1.0 开发环境 ###

> 同上一篇文章 Spring 入门实战（四） aop

### 2.0 准备工作 ###

> 由于本篇还是基于aop的 所以我们还是基于上节的代码 做一些相应改动即可

#### 2.1 主业务模块 Affairs.java 同上一篇文章 ####

#### 2.2 切面功能类 Function.java ####

package com.ccut.aop;
    
    import org.aspectj.lang.ProceedingJoinPoint;
    import org.aspectj.lang.annotation.After;
    import org.aspectj.lang.annotation.AfterReturning;
    import org.aspectj.lang.annotation.AfterThrowing;
    import org.aspectj.lang.annotation.Around;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.annotation.Pointcut;
    
    @Aspect
    public class Function { 
            private String fmessage;
            private String mmessage;
            public Function(){}
            public String getFmessage() {
                return fmessage;
            }
            public void setFmessage(String fmessage) {
                this.fmessage = fmessage;
            }
            public String getMmessage() {
                return mmessage;
            }
            public void setMmessage(String mmessage) {
                this.mmessage = mmessage;
            }
            @Pointcut("execution(* com.ccut.aop.Affairs.PersonA())")
            public void cut2(){};
            //before增强
            @Before(value="cut2()")
            public void f(){
                System.out.println(this.getFmessage());
            }
            //环绕增强
            @Around(value="cut2()")
            public void around(ProceedingJoinPoint pj){
                System.out.println("在目标函数之前执行");
                try {
                    pj.proceed();
                } catch (Throwable e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }finally{
                    System.out.println("在目标函数之后执行");
                }
            }
            //after增强
            @After(value="cut2()")
            public void m(){
                System.out.println(this.getMmessage());
            }
            //返回增强
            @AfterReturning(pointcut="execution(* com.ccut..*(..))",returning = "msg")
            public void mess(String msg){
                System.out.println(msg+" 这是返回后的信息");
            }
            //异常增强
            @AfterThrowing(value="cut2()",throwing="ex")
            public void err(Throwable ex){
                System.out.println("这个错误是："+ex);
            }
    
    }

#### 2.3 测试类Test.java ####

package com.ccut.test;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    import com.ccut.aop.Affairs;
    
    public class Test {
        public static void main(String[] args) {
            ApplicationContext applicationContext = new ClassPathXmlApplicationContext("./resources/aop.xml");
            Affairs affairs = (Affairs) applicationContext.getBean("affairs");
            affairs.PersonA();
            affairs.PersonB();
    
            affairs.getMessage1();
            affairs.error();
    
        }
    }

#### 2.4 配置文件 aop.xml ####

<?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" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">
    
    
        <aop:aspectj-autoproxy/>
    
        <bean id="affairs" class = "com.ccut.aop.Affairs">
            <property name="message1" value="我就是 A 啊 这有什么疑问吗？"/>
            <property name="message2" value="我就是 B 啊 这有什么疑问吗？"/>
        </bean>
    
        <bean id = "function" class="com.ccut.aop.Function">
            <property name="fmessage" value="我可能在你前面执行！"></property>
            <property name="mmessage" value="我可能在你后面执行呢！"></property>
        </bean>
    
    
    
        </beans>

### 3.0 工程目录 ###

![这里写图片描述][70]

### 4.0 执行结果 ###

![这里写图片描述][70 1]

> 几点说明

1.  @Aspect 代表这个类是切片类
2.  @Pointcut(“execution(\* com.ccut.aop.Affairs.PersonA())”)  
    public void cut2()\{\}; 定义切入点为 com.ccut.aop.Affairs.下的PersonA() 方法 切入点的名字叫做cut2,相当于xml中的id
3.  @Before(value=”cut2()”) value的值指向切入点id
4.  @AfterReturning(pointcut=”execution(\* com.ccut..\*(..))”,returning = “msg”) 除了用value外还可以自定义切入点
5.  配置文件中 < aop:aspectj-autoproxy/>代表启用aop注释 这样就不需要在xml配置文件中写代码了

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[70]: /images/20220528/e7b942d78a43429b921dce6af9df411f.png
[70 1]: /images/20220528/f350bc3a80bf414a973ac0ea72d5d641.png