spring-xml实现aop-通知的种类

如果本代码有疑问，请访问spring-aop快速入门或者spring-aop动态代理技术（底层分析）

1.导入aop的相关坐标

<dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>1.8.13</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>5.0.5.RELEASE</version>
    </dependency>

2.创建目标接口和目标类

public interface TargetInterface {
    public void save();
}

public class Target implements TargetInterface{
    public void save() {
        System.out.println("save running....");
    }
}

3.创建切面类

public class MyAspect {

    public void before(){
        System.out.println("前置增强...");
    }
    public void afterReturning(){
        System.out.println("后置增强...");
    }
    //ProceedingJoinPoint://切入点
    public Object around(ProceedingJoinPoint point) throws Throwable {      
        System.out.println("环绕前增强...");
        //切点方法,spring封装好的
        Object proceed = point.proceed();
        System.out.println("环绕后增强...");
        return proceed;
    }
}

4.将目标和切面类的对象创建权交给spring

<?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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

<!--    配置目标对象-->
    <bean id="target" class="com.hao.aop.Target"/>

<!--    切面对象-->
    <bean id="aspect" class="com.hao.aop.MyAspect"></bean>
</beans>

5.在applicationContext.xml中配置织入关系

<?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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

<!--    配置目标对象-->
    <bean id="target" class="com.hao.aop.Target"/>

<!--    切面对象-->
    <bean id="aspect" class="com.hao.aop.MyAspect"></bean>
<!--    配置织入：告诉spring框架哪些方法需要进行哪些增强（前置增强、后置增强）-->
    <aop:config>
<!--        声明切面 切面=切点+通知-->
        <aop:aspect ref="aspect">
            <aop:before method="before" pointcut="execution(public void com.hao.aop.Target.save())"></aop:before>
            <aop:after method="afterReturning" pointcut="execution(public void com.hao.aop.Target.save())"></aop:after>
            <aop:around method="around" pointcut="execution(public void com.hao.aop.Target.save())"></aop:around>
        </aop:aspect>
    </aop:config>
</beans>

结果：

---

切点表达式的抽取，为了方便以后更改

<?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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

<!--    配置目标对象-->
    <bean id="target" class="com.hao.aop.Target"/>

<!--    切面对象-->
    <bean id="aspect" class="com.hao.aop.MyAspect"></bean>
<!--    配置织入：告诉spring框架哪些方法需要进行哪些增强（前置增强、后置增强）-->
    <aop:config>
<!--        声明切面 切面=切点+通知-->
        <aop:aspect ref="aspect">
<!--            抽取切入点表达式-->
            <aop:pointcut id="myPointcut" expression="execution(public void com.hao.aop.Target.save())"></aop:pointcut>
            <aop:before method="before" pointcut-ref="myPointcut"></aop:before>
            <aop:after method="afterReturning" pointcut-ref="myPointcut"></aop:after>
            <aop:around method="around" pointcut-ref="myPointcut"></aop:around>
        </aop:aspect>
    </aop:config>
</beans>