【 Aspect 案例讲解（基于xml） 】

第一步：导包

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.ys</groupId>
    <artifactId>Spring</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.3.19.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.3.19.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.19.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
            <version>4.3.19.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>4.3.19.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>aopalliance</groupId>
            <artifactId>aopalliance</artifactId>
            <version>1.0</version>
        </dependency>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>4.3.19.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

第二步：实现类和切面类

package cn.ys.service;

public interface UserService {

    public void addUser();
    public void updateUser();
    public void deleteUser();

}

package cn.ys.service;

public class UserServiceImpl implements UserService {

    public void addUser() {
        System.out.println("添加用户......");
    }

    public void updateUser() {
        System.out.println("更新用户......");
    }

    public void deleteUser() {
        System.out.println("删除用户......");
    }

}

package cn.ys.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

public class MyAspect {

    public void myBefore(JoinPoint jp){
        System.out.println("1.前置通知..." + jp.getSignature().getName()); // 连接点方法名
    }

    public void myAfterReturning(JoinPoint jp,Object retValue){
        System.out.println("3.后置通知..." +  jp.getSignature().getName());
        System.out.println("返回值:" + retValue);
    }

    public Object myAround(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("2.环绕通知...开启事务..." + pjp.getSignature().getName());
        //放行
        Object retObj = pjp.proceed();
        System.out.println("4.环绕通知....提交事务...");
        return retObj;
    }

    public void myAfterThrowing(JoinPoint jp,Throwable e){
        System.out.println("异常通知..." + jp.getSignature().getName() + "===" + e.getMessage() );
    }

    public void myAfter(JoinPoint jp){
        System.out.println("最终通知..." + jp.getSignature().getName());
    }

}

第三步：spring 的 xml 配置

<?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UserService-->
    <bean id="userService" class="cn.ys.service.UserServiceImpl"></bean>

    <!-- 配置切面对象-->
    <bean id="myAspect" class="cn.ys.aspect.MyAspect"></bean>

    <!-- 配置 aop -->
    <aop:config>
        <!-- aop:指定切面-->
        <aop:aspect ref="myAspect">
            <!--定义一个切入点-->
            <aop:pointcut id="myPointcut" expression="execution(* cn.ys.service.UserServiceImpl.*(..))"/>

            <!-- 配置前置通知...-->
            <aop:before method="myBefore" pointcut-ref="myPointcut" />

            <!-- 配置后置通知...-->
            <aop:after-returning method="myAfterReturning" pointcut-ref="myPointcut" returning="retValue"/>

            <!--配置环绕通知-->
            <aop:around method="myAround" pointcut-ref="myPointcut"></aop:around>

            <!-- 配置异常通知
            throwing="e" 值，是方法的参数名
            -->
            <aop:after-throwing method="myAfterThrowing" pointcut-ref="myPointcut" throwing="e"/>

            <!--配置最终通知:不管有没有异常，最终通知都会执行-->
            <aop:after method="myAfter" pointcut-ref="myPointcut"></aop:after>
        </aop:aspect>
    </aop:config>

</beans>

第四步：测试

package cn.ys.spring;

import cn.ys.service.UserService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class testSpring {

    @Test
    public void testSpringCglib() throws Exception {

        //获取Spring容器中代理对象
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");

        UserService userService = (UserService) context.getBean("userService");

        userService.deleteUser();

    }

}

控制台打印

C:\Java\jdk1.8.0_181\bin\java.exe -ea -Didea.test.cyclic.buffer.size=1048576 "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.1\lib\idea_rt.jar=51016:C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.1\lib\idea_rt.jar;C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.1\plugins\junit\lib\junit-rt.jar;C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.1\plugins\junit\lib\junit5-rt.jar;C:\Java\jdk1.8.0_181\jre\lib\charsets.jar;C:\Java\jdk1.8.0_181\jre\lib\deploy.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\access-bridge-64.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\cldrdata.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\dnsns.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\jaccess.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\jfxrt.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\localedata.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\nashorn.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\sunec.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\sunjce_provider.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\sunmscapi.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\sunpkcs11.jar;C:\Java\jdk1.8.0_181\jre\lib\ext\zipfs.jar;C:\Java\jdk1.8.0_181\jre\lib\javaws.jar;C:\Java\jdk1.8.0_181\jre\lib\jce.jar;C:\Java\jdk1.8.0_181\jre\lib\jfr.jar;C:\Java\jdk1.8.0_181\jre\lib\jfxswt.jar;C:\Java\jdk1.8.0_181\jre\lib\jsse.jar;C:\Java\jdk1.8.0_181\jre\lib\management-agent.jar;C:\Java\jdk1.8.0_181\jre\lib\plugin.jar;C:\Java\jdk1.8.0_181\jre\lib\resources.jar;C:\Java\jdk1.8.0_181\jre\lib\rt.jar;C:\Users\ys951\Desktop\JavaSETest\JavaEE\Spring\target\test-classes;C:\Users\ys951\Desktop\JavaSETest\JavaEE\Spring\target\classes;C:\Users\ys951\.m2\repository\org\springframework\spring-core\4.3.19.RELEASE\spring-core-4.3.19.RELEASE.jar;C:\Users\ys951\.m2\repository\org\springframework\spring-beans\4.3.19.RELEASE\spring-beans-4.3.19.RELEASE.jar;C:\Users\ys951\.m2\repository\org\springframework\spring-context\4.3.19.RELEASE\spring-context-4.3.19.RELEASE.jar;C:\Users\ys951\.m2\repository\org\springframework\spring-expression\4.3.19.RELEASE\spring-expression-4.3.19.RELEASE.jar;C:\Users\ys951\.m2\repository\commons-logging\commons-logging\1.2\commons-logging-1.2.jar;C:\Users\ys951\.m2\repository\org\springframework\spring-aop\4.3.19.RELEASE\spring-aop-4.3.19.RELEASE.jar;C:\Users\ys951\.m2\repository\aopalliance\aopalliance\1.0\aopalliance-1.0.jar;C:\Users\ys951\.m2\repository\org\aspectj\aspectjweaver\1.9.2\aspectjweaver-1.9.2.jar;C:\Users\ys951\.m2\repository\org\springframework\spring-aspects\4.3.19.RELEASE\spring-aspects-4.3.19.RELEASE.jar;C:\Users\ys951\.m2\repository\junit\junit\4.12\junit-4.12.jar;C:\Users\ys951\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar" com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit4 cn.ys.spring.testSpring,testSpringCglib
二月 27, 2019 10:32:03 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@555590: startup date [Wed Feb 27 10:32:03 CST 2019]; root of context hierarchy
二月 27, 2019 10:32:03 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [beans.xml]
1.前置通知...deleteUser
2.环绕通知...开启事务...deleteUser
删除用户......
最终通知...deleteUser
4.环绕通知....提交事务...
3.后置通知...deleteUser
返回值:null

Process finished with exit code 0