AOP AspectJ注解

概念：

切面(aspect)：用来切插业务方法的类。
连接点(joinpoint)：是切面类和业务类的连接点，其实就是封装了业务方法的一些基本属性，作为通知的参数来解析。
通知(advice)：在切面类中，声明对业务方法做额外处理的方法。
切入点(pointcut)：业务类中指定的方法，作为切面切入的点。其实就是指定某个方法作为切面切的地方。
目标对象(target object)：被代理对象。
AOP代理(aop proxy)：代理对象。

AOP通知类型：
前置通知(before advice)：在切入点之前执行。
后置通知(after returning advice)：在切入点执行完成后，执行通知。
环绕通知(around advice)：包围切入点，调用方法前后完成自定义行为。
异常通知(after throwing advice)：在切入点抛出异常后，执行通知

依赖包：

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.6.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjrt -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.8.10</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.10</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/cglib/cglib -->
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>3.2.5</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>4.3.6.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.3.6.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.3.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.3.6.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.3.6.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>

Code:

package com.qhong;


import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Component;

public class Main {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        Person person=(Person)context.getBean("babyPerson");
        person.eatBreakfast();
        System.out.println("===================================================");
        person.eatLunch();
        System.out.println("===================================================");
        person.eatSupper();
        System.out.println("===================================================");
        person.drink("可乐");
        System.out.println("===================================================");
   }
}

interface Person {
    public void eatBreakfast();
    public void eatLunch();
    public void eatSupper();
    public String drink(String name);
}

@Component
class BabyPerson implements Person{

    @Override
    public void eatBreakfast() {
        System.out.println("小Baby正在吃早餐");
    }

    @Override
    public void eatLunch() {
        System.out.println("小Baby正在吃午餐");
    }

    @Override
    public void eatSupper() {
        System.out.println("小Baby正在吃晚餐");
    }

    @Override
    public String drink(String name) {
        return "小Baby在喝："+name;
    }
}

@Component
@Aspect
class AdivceMethod {

    @Before("execution(* com.qhong.BabyPerson.*(..))")
    // 匹配BabyPerson类所有的方法,注意*和com之间有个空格
    public void beforeEat() {
        System.out
                .println("-------------------这里是前置增强，吃饭之前先洗小手！--------------------");
    }

    @After("execution(* eatLunch(..))")
    // 匹配该工程下所有的eatLunch方法
    public void afterEat() {
        System.out
                .println("-------------------这里是后置增强，午饭吃完要睡午觉！--------------------");
    }

    @Around("execution(* com.qhong.BabyPerson.eatSupper())")
    // 匹配该工程下BabyPerson的eatLunch方法
    public Object aroundEat(ProceedingJoinPoint pjp) throws Throwable {
        System.out
                .println("-------------------这里是环绕增强，吃晚饭前先玩一玩！-------------------");
        Object retVal = pjp.proceed();
        System.out
                .println("-------------------这里是环绕增强，晚饭吃完后要得睡觉了！-------------------");
        return retVal;
    }
    @AfterReturning(returning="rvt",pointcut="execution(* com.qhong.BabyPerson.drink(..))")
    public void log(Object rvt) {
        System.out
                .println("-------------------这里是AfterReturning增强-------------------");
        System.out.println("获取小Baby正在喝的饮料"+rvt);
        System.out.println("记录每天喝的饮料容量");

    }
}

beans.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: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-3.0.xsd
           http://www.springframework.org/schema/aop
           http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <!-- 指定自动搜索bean组件、自动搜索切面类 -->
    <context:component-scan base-package="com.qhong"/>
    <!-- 启动@AspectJ支持 -->
    <!-- proxy-target-class默认"false",更改为"ture"使用CGLib动态代理 -->
    <aop:aspectj-autoproxy proxy-target-class="true"/>
</beans>

Result:

-------------------这里是前置增强，吃饭之前先洗小手！--------------------
小Baby正在吃早餐
===================================================
-------------------这里是前置增强，吃饭之前先洗小手！--------------------
小Baby正在吃午餐
-------------------这里是后置增强，午饭吃完要睡午觉！--------------------
===================================================
-------------------这里是环绕增强，吃晚饭前先玩一玩！-------------------
-------------------这里是前置增强，吃饭之前先洗小手！--------------------
小Baby正在吃晚餐
-------------------这里是环绕增强，晚饭吃完后要得睡觉了！-------------------
===================================================
-------------------这里是前置增强，吃饭之前先洗小手！--------------------
-------------------这里是AfterReturning增强-------------------
获取小Baby正在喝的饮料小Baby在喝：可乐
记录每天喝的饮料容量
===================================================

Spring + AspectJ（基于注解：通过 AspectJ execution 表达式拦截方法）

package com.qhong;


import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Component;

public class Main {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
        com.qhong.Greeting greeting = (com.qhong.Greeting) context.getBean("greetingImpl");
        greeting.sayHello("Jack");
    }
}

interface Greeting {
    void sayHello(String name);
}

@Component
class GreetingImpl implements Greeting {
    @Override
    public void sayHello(String name) {
        System.out.println("Hello! " + name);
    }
}

@Aspect
@Component
class GreetingAspect {
    @Around("execution(* com.qhong.GreetingImpl.*(..))")
    public Object around(ProceedingJoinPoint pjp) throws Throwable {
        before();
        Object result = pjp.proceed();
        after();
        return result;
    }

    private void before() {
        System.out.println("Before");
    }

    private void after() {
        System.out.println("After");
    }
}

spring.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: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">

    <context:component-scan base-package="com.qhong"/>

    <aop:aspectj-autoproxy proxy-target-class="true"/>
</beans>

Result:

Before
Hello! Jack
After

遇到的bug

java.lang.NoClassDefFoundError: org/springframework/beans/factory/NoUniqueBeanDefinitionException

遇到这个问题应该是groupid是org.springframework的各个依赖之间版本相差太大造成的问题，全都改成统一的就ok了。

http://tonylit.me/2016/06/29/spring%20aop-AspectJ%E6%B3%A8%E8%A7%A3%E6%96%B9%E5%BC%8F/

http://www.yiibai.com/spring/spring-aop-aspectj-annotation-example.html

http://blog.csdn.net/xiaoxian8023/article/details/17285809

http://www.kancloud.cn/evankaka/springlearning/119670

http://git.oschina.net/lujianing/aop_demo

https://my.oschina.net/huangyong/blog/159788

https://my.oschina.net/huangyong/blog/161338

https://my.oschina.net/huangyong/blog/161402

https://my.oschina.net/huangyong/blog/160769

https://my.oschina.net/huangyong/blog/170494