Spring示例：第一个AOP

首先有如下两个关于开发过程的概念：

• 纵向编程，代码较为重复
• 横向编程，重复代码形成切面织入节点

下面编写实例：

1. 添加额外倚赖

<!-- https://mvnrepository.com/artifact/org.aspectj/aspectjrt -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.9.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.1</version>
        </dependency>

2. 新建类

public class BeforeAdvice {

    public void methodBefore(){
        System.out.println("我在方法之前执行");
    }

}

public class ProviderService {
    public void add(){
        System.out.println("添加了一个供应商");
    }
}

3. 配置文件

<?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:c="http://www.springframework.org/schema/c"
       xmlns:cache="http://www.springframework.org/schema/cache"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jdbc="http://www.springframework.org/schema/jdbc"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:lang="http://www.springframework.org/schema/lang"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:task="http://www.springframework.org/schema/task"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.3.xsd
		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.3.xsd
		http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.3.xsd
		http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache-4.3.xsd
		http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.3.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-4.3.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd ">


    <!--【第一步：激活代理】 aop是基于代理完成的，所以我们要激活我们的自动代理-->
    <aop:aspectj-autoproxy/>

    <!--【第二步：注册一个切面要使用的类】-->
    <bean class="com.zt.advice.BeforeAdvice" id="beforeAdvice">
    </bean>

    <bean class="com.zt.service.ProviderService" id="providerService">
    </bean>

    <!--【第三步：配置切入点等等信息】-->
    <aop:config >
        <aop:aspect id="beforeAspect" ref="beforeAdvice">
            <!--
                aop:before 表明它是前置通知
                method 指明了它是哪个方法来切
                pointcut：切入点
                        *包下的*类*方法
            -->
            <aop:before method="methodBefore" pointcut="execution(* com.zt.service.ProviderService(..))"></aop:before>
        </aop:aspect>
    </aop:config>


</beans>

带张图解如下：

关于execution部分的解释如下：


4. 测试

@Test
    public void m1(){
        ApplicationContext ctx = new ClassPathXmlApplicationContext("spring/applicationContext.xml");

        ctx.getBean("beforeAdvice", BeforeAdvice.class);
        //如果不是spring容器管理的bean，那么织入行为无法生效
       // ProviderService providerService = new ProviderService();
        /*ProviderService providerService = ctx.getBean("providerService", ProviderService.class);
        providerService.add();*/
    }