Spring-AOP用法总结

前言

    Spring AOP的实现方法很多，在项目开发中具体采用什么方式，需要按实际情况来选择，每一种的用法，有其一定的实用价值，所以本文将各种使用方法进行了具体实现。主要包括Advice的before、after、throwing、around四种拦截方式的实现，如何进行正则匹配，自动化代理及AspectJ注解形式的实现。

AOP的定义

     Spring AOP(Aspect-oriented programming) 面向切面编程，是一种特殊的拦截器，将一组程序中的公共部分抽离出来进行单独管理，降低程序的耦合度，aop和oo互为补充，面向对象编程将程序分解成各个层次的对象，而面向切面编程将程序运行过程分解成各个切面。也可以这样理解，面向对象编程是从静态角度考虑程序结构，面向切面编程是从动态角度考虑程序运行过程。

   

 AOP中6个要素

（1）通知（增强）Advice

　　通知定义了切面是什么以及何时使用，应该应用在某个方法被调用之前？之后？还是抛出异常时？等等。

（2）连接点 Join point

　　连接点是在应用执行过程中能够插入切面的一个点。这个点可以是调用方法时，抛出异常时，甚至修改一个字段时。切面代码可以利用这些点插入到应用的正常流程中，并添加新的行为。

（3）切点 Pointcut

　　切点有助于缩小切面所通知的连接点的范围。如果说通知定义了切面的“什么”和“何时”的话，那么切点就定义了“何处”，切点会匹配通知所要织入的一个或多个连接点，一般常用正则表达式

定义所匹配的类和方法名称来指定这些切点。

（4）切面 Aspect

　　切面是通知和切点的结合。通知和切点定义了切面的全部内容——它是什么，在何时何处完成其功能。

（5）引入 Introduction

　　引入允许我们向现有的类添加新方法或属性，从而无需修改这些现有类的情况下，让他们具有新的行为和状态。

（6）织入 Weaving

　　在过去我常常把织入与引入的概念混淆，我是这样来辨别的，“引入”我把它看做是一个定义，也就是一个名词，而“织入”我把它看做是一个动作，一个动词，也就是切面在指定的连接点被织

入到目标对象中。

AOP用法总结

（1）Before advice 在方法执行前执行。

（2）After  returning  advice 在方法执行后返回一个结果后执行。

（3）After  throwing advice 在方法执行过程中抛出异常的时候执行。

（4）Around  advice 在方法执行前后和抛出异常时执行，相当于综合了以上三种通知。

（5）基于正则表达式，对符合匹配规则类或方法进行拦截处理。

（6）基于自动代理，简少配置。

（7）基于AspectJ注解形式,包括execution 表达式、@DeclareParents 注解、自动代理。

实例

1. Before advice 在方法执行前执行

创建Product产品类

package com.jk.work.aopone;
/**
 * Title: 产品
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-18
 * @version: 1.0
 */
public class Product {
    private  String  name;
    private  String  type;
    private   int    size;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public  void  printName(){
        System.out.println("Product name "+ this.name);
    }

    public  void  printType(){
        System.out.println("Product type "+this.type);
    }

    public  void  printThrowException(){
        throw  new  IllegalArgumentException();
    }
}

创建BeforeMethod类

package com.jk.work.aopone;
import org.springframework.aop.MethodBeforeAdvice;
import java.lang.reflect.Method;
/**
 * Title: BeforeMethod
 * Description: 在方法执行前执行
 *
 * @author jihuan
 * @create 2017-05-19
 * @version: 1.0
 */
public class BeforeMethod implements MethodBeforeAdvice {
    @Override
    public void before(Method method, Object[] objects, Object o) throws Throwable {
        System.out.println("Before  Method");
        System.out.println("--------------------");
    }
}

创建配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="product" class="com.jk.work.aopone.Product">
        <property name="name" value="p2p p2p p2p" />
        <property name="type" value="one year"/>
        <property name="size" value="30000" />
    </bean>

    <bean id="beforeMethodBean" class="com.jk.work.aopone.BeforeMethod" />

    <bean id="productProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target" ref="product"/>
        <property name="interceptorNames">
            <list>
                <value>beforeMethodBean</value>
            </list>
        </property>
        <property name="proxyTargetClass" value="true"/> <!-- true 表 cglib,false 为jdkproxy(需要property 引入接口)-->
    </bean>
</beans>

创建测试类Test.java

package com.jk.work.aopone;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-19
 * @version: 1.0
 */
public class Test {

    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        Product   product  =   (Product) context.getBean("productProxy");
        System.out.println("---------------------");
        product.printName();
        System.out.println("---------------------");
        product.printType();
        System.out.println("----------------------");
        try{
            product.printThrowException();
        }catch(Exception e){
        }
    }
}

 运行结果：

---------------------
Before  Method
--------------------
Product name p2p p2p p2p
---------------------
Before  Method
--------------------
Product type one year
----------------------
Before  Method
--------------------

  测试类可以采用编程式调用，简单实现： 

package com.jk.work.aopone;
import org.springframework.aop.framework.ProxyFactory;
/**
 * Title: 编程式
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-19 00:26
 * @version: 1.0
 */
public class Test2 {

    public static void main(String[] args) {
        ProxyFactory proxyFactory=new ProxyFactory() ;
        Product product1=new Product();
        product1.setName("p2p");
        proxyFactory.setTarget(product1);
        proxyFactory.addAdvice(new BeforeMethod());
        Product product=(Product)proxyFactory.getProxy();
        product.printName();
    }
}

运行结果：

Before  Method
--------------------
Product name p2p

2.After  returning  advice 方法之后执行

创建AfterMethod类 

package com.jk.work.aopone;
import org.springframework.aop.AfterReturningAdvice;
import java.lang.reflect.Method;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-19 00:09
 * @version: 1.0
 */
public class AfterMethod implements AfterReturningAdvice {
    @Override
    public void afterReturning(Object o, Method method, Object[] objects, Object o1) throws Throwable {
        System.out.println("-------------------");
        System.out.println("After  method ");
    }
}

 创建配置文件 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="product" class="com.jk.work.aopone.Product">
        <property name="name" value="p2p p2p p2p" />
        <property name="type" value="one year"/>
        <property name="size" value="30000" />
    </bean>

    <bean id="afterMethodBean" class="com.jk.work.aopone.AfterMethod" />

    <bean id="productProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target" ref="product"/>
        <property name="interceptorNames">
            <list>
                <value>afterMethodBean</value>
            </list>
        </property>
        <property name="proxyTargetClass" value="true"/> <!-- true 表 cglib,false 为jdkproxy(需要property 引入接口)-->
    </bean>
</beans> 

创建测试类复用Test.java

运行结果： 

---------------------
Product name p2p p2p p2p
-------------------
After  method 
---------------------
Product type one year
-------------------
After  method 
----------------------

3. After  throwing advice 在方法执行过程中抛出异常的时候执行

创建ThrowException类

package com.jk.work.aopone;
import org.springframework.aop.ThrowsAdvice;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-19
 * @version: 1.0
 */
public class ThrowException  implements ThrowsAdvice {
    public  void  afterThrowing(IllegalArgumentException e)  throws  Throwable{
        System.out.println("after Throwing  Exception");
    }
}

 创建配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="product" class="com.jk.work.aopone.Product">
        <property name="name" value="p2p p2p p2p" />
        <property name="type" value="one year"/>
        <property name="size" value="30000" />
    </bean>

    <bean id="throwException" class="com.jk.work.aopone.ThrowException" />

    <bean id="productProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target" ref="product"/>
        <property name="interceptorNames">
            <list>
                <value>throwException</value>
            </list>
        </property>
        <property name="proxyTargetClass" value="true"/> <!-- true 表 cglib,false 为jdkproxy(需要property 引入接口)-->
    </bean>
</beans>

运行结果

---------------------
Product name p2p p2p p2p
---------------------
Product type one year
----------------------
after Throwing  Exception

4. Around  advice 在方法执行前后和抛出异常时执行，相当于综合了以上三种通知 

创建AroundMethod类

package com.jk.work.aopone;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import java.util.Arrays;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-19 
 * @version: 1.0
 */
public class AroundMethod implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
        System.out.println("method  name:" + methodInvocation.getMethod().getName());
        System.out.println("method  arguments" + Arrays.toString(methodInvocation.getArguments()));
        System.out.println("Around  method : before ");
        try{
            Object result = methodInvocation.proceed();
            System.out.println("Around method : after ");
            return  result;
        }catch(IllegalArgumentException e){
            System.out.println("Around method : throw  an  exception ");
            throw  e;
        }
    }
}

创建配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="product" class="com.jk.work.aopone.Product">
        <property name="name" value="p2p p2p p2p" />
        <property name="type" value="one year"/>
        <property name="size" value="30000" />
    </bean>

    <bean id="aroundMethod"  class="com.jk.work.aopone.AroundMethod" />

    <bean id="productProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target" ref="product"/>
        <property name="interceptorNames">
            <list>
                <value>aroundMethod</value>
            </list>
        </property>
        <property name="proxyTargetClass" value="true"/> <!-- true 表 cglib,false 为jdkproxy(需要property 引入接口)-->
    </bean>
</beans>

运行结果

---------------------
method  name:printName
method  arguments[]
Around  method : before 
Product name p2p p2p p2p
Around method : after 
---------------------
method  name:printType
method  arguments[]
Around  method : before 
Product type one year
Around method : after 
----------------------
method  name:printThrowException
method  arguments[]
Around  method : before 
Around method : throw  an  exception 

5. 基于正则表达式的实现

    采用RegexpMethodPointcutAdvisor来实现。采用的正则匹配规则，大概有四点，举例说明：

com.service..* 和 com.service..*Service..* 和 .*get.* 和 .get.*

第一个表达式匹配的应该是com.service包下的所有方法
第二个表达式匹配的应该是com.service包下所有类名以Service结尾的所有方法
第三个表达式匹配的应该是所有类中含有get的方法
第四个表达式匹配的应该是所有类中以get为前缀的方法

具体如何实现，见下方实例：

创建Garden接口

package com.jk.work.aoptwo;

/**
 * Created by jihuan on 17/5/20.
 */
public interface Garden {

    void fruitPlant();

    void fruitGrow();

    void fruitHarvest();
}

 创建Garden实现类

package com.jk.work.aoptwo;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20
 * @version: 1.0
 */
public class AppleGarden implements Garden{
    @Override
    public void fruitPlant() {
        System.out.println("Apple plant...");
    }

    @Override
    public void fruitGrow() {
        System.out.println("Apple grow...");
    }

    @Override
    public void fruitHarvest() {
        System.out.println("Apple harvest...");
    }
}

 创建拦截类，采用MethodInterceptor，实现方法前后拦截

package com.jk.work.aoptwo;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20
 * @version: 1.0
 */
public class GardenAroundAdvice implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation methodInvocation) throws Throwable {
        before();
        Object result=methodInvocation.proceed();
        after();
        return result;
    }
    private void before(){
        System.out.println("before......");
    }
    private void after(){
        System.out.println("after......");
    }
} 

创建配置文件，AppleGarden下所有以fruit开头的方法进行切面拦截

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">  

     <!--果园-->
    <bean id="appleGarden" class="com.jk.work.aoptwo.AppleGarden" />
    <bean id="gardenAroundAdvice" class="com.jk.work.aoptwo.GardenAroundAdvice" />
    <bean id="gardenAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice" ref="gardenAroundAdvice" />
        <property name="pattern" value="com.jk.work.aoptwo.AppleGarden.fruit.*" />
    </bean>

    <bean id="productProxy" class="org.springframework.aop.framework.ProxyFactoryBean">
        <property name="target" ref="appleGarden"/>
        <property name="interceptorNames">
            <list>
                <value>gardenAdvisor</value>
            </list>
        </property>
        <property name="proxyTargetClass" value="true"/> <!-- true 表 cglib,false 为jdkproxy(需要property 引入接口)-->
    </bean>
</beans>

 测试类

package com.jk.work.aoptwo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20
 * @version: 1.0
 */
public class Test {
    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        AppleGarden appleGarden  =   (AppleGarden) context.getBean("productProxy");
        System.out.println("----------1-----------");
        appleGarden.fruitPlant();
        System.out.println("----------2----------");
        appleGarden.fruitGrow();
        System.out.println("----------3-----------");
        appleGarden.fruitHarvest();

    }
}

 运行效果：

----------1-----------
before......
Apple plant...
after......
----------2----------
before......
Apple grow...
after......
----------3-----------
before......
Apple harvest...
after......

Process finished with exit code 0

6. 基于自动代理的实现

采用自动代理的好处，可以减少配置，简化开发，spring的自动代理，采用了三种方式：

1）Advisor形式，实现类为DefaultAdvisorAutoProxyCreator；

2）Bean形式，实现类为BeanNameAutoProxyCreator；

3）AspjectJ注解形式，实现方式是@Aspect。

具体实例

 Advisor形式，实现类为DefaultAdvisorAutoProxyCreator

创建sprng-aop.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
     <!--果园-->
    <bean id="appleGarden" class="com.jk.work.aoptwo.AppleGarden" />
    <bean id="gardenAroundAdvice" class="com.jk.work.aoptwo.GardenAroundAdvice" />
    <bean id="gardenAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice" ref="gardenAroundAdvice" />
        <property name="pattern" value="com.jk.work.aoptwo.AppleGarden.fruit.*" />
    </bean>
    <!--自动代理-->
    <bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator">
      <property name="optimize" value="true"/><!-- true 自动寻找代理类，有接口，使用jdkproxy，否则采用cglib-->
    </bean>
</beans>

 测试类：

package com.jk.work.aoptwo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20
 * @version: 1.0
 */
public class Test2 {
    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        AppleGarden appleGarden  =   (AppleGarden) context.getBean("appleGarden");
        System.out.println("----------1-----------");
        appleGarden.fruitPlant();
        System.out.println("----------2----------");
        appleGarden.fruitGrow();
        System.out.println("----------3-----------");
        appleGarden.fruitHarvest();
    }
}

 运行效果

----------1-----------
before......
Apple plant...
after......
----------2----------
before......
Apple grow...
after......
----------3-----------
before......
Apple harvest...
after......

Bean形式，实现类为BeanNameAutoProxyCreator

创建spring-aop.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
     <!--果园-->
    <bean id="appleGarden" class="com.jk.work.aoptwo.AppleGarden" />
    <bean id="gardenAroundAdvice" class="com.jk.work.aoptwo.GardenAroundAdvice" />
    <bean id="gardenAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice" ref="gardenAroundAdvice" />
        <property name="pattern" value="com.jk.work.aoptwo.AppleGarden.fruit.*" />
    </bean>

    <!--自动代理-->
    <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
        <property name="beanNames" value="*Garden" />
        <property name="interceptorNames" value="gardenAdvisor"/>
        <property name="optimize" value="true"/> <!--true 使用jdkproxy，false 采用cglib-->
    </bean>
</beans>

  测试类：

package com.jk.work.aoptwo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20
 * @version: 1.0
 */
public class Test2 {
    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        AppleGarden appleGarden  =   (AppleGarden) context.getBean("appleGarden");
        System.out.println("----------1-----------");
        appleGarden.fruitPlant();
        System.out.println("----------2----------");
        appleGarden.fruitGrow();
        System.out.println("----------3-----------");
        appleGarden.fruitHarvest();
    }
}

 运行效果

----------1-----------
before......
Apple plant...
after......
----------2----------
before......
Apple grow...
after......
----------3-----------
before......
Apple harvest...
after......

 AspjectJ注解形式，实现类是AnnotationAwareAspectJAutoProxyCreator，在AspjectJ注解部分说明。

 

7. AspectJ注解

 AspectJ注解方式，采用execution表达式进行切面拦截

创建spring-aop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"
       xmlns:context="http://www.springframework.org/schema/context"
       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.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.*"/>
     <!--果园-->
    <bean id="appleGarden" class="com.jk.work.aoptwo.AppleGarden" />
    <bean id="gardenAroundAdvice" class="com.jk.work.aoptwo.GardenAroundAdvice" />
    <bean id="gardenAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice" ref="gardenAroundAdvice" />
        <property name="pattern" value="com.jk.work.aoptwo.AppleGarden.fruit.*" />
    </bean>
    <!--aspectj-->
    <aop:aspectj-autoproxy proxy-target-class="true"/>
</beans>

  创建AroundAspect 拦截类

package com.jk.work.aoptwo;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20
 * @version: 1.0
 */
@Aspect
@Component
public class AroundAspect {
    @Around("execution(* com.jk.work.aoptwo.AppleGarden.*(..))")
    public Object around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable{
        handleBefore();
        Object rs=proceedingJoinPoint.proceed();
        handleAfter();
        return  rs;
    }

    private void handleBefore(){
        System.out.println("=====before=====");
    }
    private void handleAfter(){
        System.out.println("=====after=====");
    }
}

 测试类

package com.jk.work.aoptwo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20
 * @version: 1.0
 */
public class Test2 {
    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        AppleGarden appleGarden  =   (AppleGarden) context.getBean("appleGarden");
        System.out.println("----------1-----------");
        appleGarden.fruitPlant();
        System.out.println("----------2----------");
        appleGarden.fruitGrow();
        System.out.println("----------3-----------");
        appleGarden.fruitHarvest();
    }
}

 运行效果

----------1-----------
=====before=====
Apple plant...
=====after=====
----------2----------
=====before=====
Apple grow...
=====after=====
----------3-----------
=====before=====
Apple harvest...
=====after=====

AspectJ @DeclareParents 注解，目标是对于一个已有的类引入新的接口，可以使用另一个接口类的功能，属于一种对类的扩展

创建新的接口Worker类

package com.jk.work.aoptwo;

/**
 * Created by jihuan on 17/5/20.
 */
public interface Worker {

    void work(String task);
} 

创建Worker的实现类

package com.jk.work.aoptwo;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20 17:43
 * @version: 1.0
 */
public class AppleWorker implements Worker{
    @Override
    public void work(String task) {
        System.out.println("start work..."+task);
    }
}

创建拦截器AroundAspect2

package com.jk.work.aoptwo;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.DeclareParents;
import org.springframework.stereotype.Component;

/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20 17:40
 * @version: 1.0
 */
@Aspect
@Component
public class AroundAspect2 {
    @DeclareParents(value = "com.jk.work.aoptwo.AppleGarden",defaultImpl =AppleWorker.class )
    private Worker worker;
}

spring-aop.xml的配置

<?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"
       xmlns:context="http://www.springframework.org/schema/context"
       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.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.*"/>
     <!--果园-->
    <bean id="appleGarden" class="com.jk.work.aoptwo.AppleGarden" />
    <bean id="gardenAroundAdvice" class="com.jk.work.aoptwo.GardenAroundAdvice" />
    <bean id="gardenAdvisor" class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
        <property name="advice" ref="gardenAroundAdvice" />
        <property name="pattern" value="com.jk.work.aoptwo.AppleGarden.fruit.*" />
    </bean>
    <!--aspectj-->
    <aop:aspectj-autoproxy proxy-target-class="true"/>
</beans>

创建测试类

package com.jk.work.aoptwo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20 17:48
 * @version: 1.0
 */
public class Test3 {
    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        AppleGarden appleGarden  =   (AppleGarden) context.getBean("appleGarden");
        Worker worker=(Worker)appleGarden;
        System.out.println("----------1-----------");
        worker.work("plant");
        appleGarden.fruitPlant();
        System.out.println("----------2----------");
        worker.work("watering");
        appleGarden.fruitGrow();
        System.out.println("----------3-----------");
        appleGarden.fruitHarvest();
        worker.work("Harvest");
    }
}

 运行效果

----------1-----------
start work...plant
Apple plant...
----------2----------
start work...watering
Apple grow...
----------3-----------
Apple harvest...
start work...Harvest

 

AspjectJ注解自动代理方式的实现

创建拦截类

package com.jk.work.aoptwo;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20 17:21
 * @version: 1.0
 */
@Aspect
@Component
public class AroundAspect {
    public Object around(ProceedingJoinPoint proceedingJoinPoint) throws Throwable{
        handleBefore();
        Object rs=proceedingJoinPoint.proceed();
        handleAfter();
        return  rs;
    }

    private void handleBefore(){
        System.out.println("=====before=====");
    }
    private void handleAfter(){
        System.out.println("=====after=====");
    }
}

spring-aop.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"
       xmlns:context="http://www.springframework.org/schema/context"
       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.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.*"/>
  
    <!--aspectj-->
    <aop:config>
        <aop:aspect ref="aroundAspect">
            <aop:around method="around" pointcut="execution(* com.jk.work.aoptwo.AppleGarden.*(..))"/>
        </aop:aspect>
    </aop:config>
    <aop:aspectj-autoproxy proxy-target-class="true"/>
</beans>

测试类

package com.jk.work.aoptwo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20 11:04
 * @version: 1.0
 */
public class Test2 {
    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        AppleGarden appleGarden  =   (AppleGarden) context.getBean("appleGarden");
        System.out.println("----------1-----------");
        appleGarden.fruitPlant();
        System.out.println("----------2----------");
        appleGarden.fruitGrow();
        System.out.println("----------3-----------");
        appleGarden.fruitHarvest();
    }
}

运行效果

package com.jk.work.aoptwo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Title: 类的主题（开发人员填写）
 * Description: 该类的功能
 *
 * @author jihuan
 * @create 2017-05-20 11:04
 * @version: 1.0
 */
public class Test2 {
    public static void main(String[] args) {
        ApplicationContext context  = new ClassPathXmlApplicationContext("classpath:spring/spring-aop.xml");
        AppleGarden appleGarden  =   (AppleGarden) context.getBean("appleGarden");
        System.out.println("----------1-----------");
        appleGarden.fruitPlant();
        System.out.println("----------2----------");
        appleGarden.fruitGrow();
        System.out.println("----------3-----------");
        appleGarden.fruitHarvest();
    }
}

总结

     AOP的用法较多，熟悉每一种用法，能更好的在项目中发挥作用。AOP其实就是一种拦截器，底层采用JDKProxy动态代理和Cglib实现动态代理。对于有接口的形式采用JDKProxy加载处理目标对象。对于没有接口的普通类采用Cglib进行对象的拦截对出。JDKProxy的底层是java反射，Cglib的底层是调asm开源包。

如需转载，请标明本文作者：源码在深山，出处：博客园，原文链接：http://www.cnblogs.com/love-jk/p/spring-api.html

参考：

1） http://blog.csdn.net/topwqp/article/details/8695180

2)   http://www.cnblogs.com/zhaozihan/p/5953063.html

3）《轻量级Java EE企业应用实战》第三版