Java基础-SSM之Spring的POJO（Plain Old Java Object）实现AOP

　　　　　　　　　　　　Java基础-SSM之Spring的POJO（Plain Old Java Object）实现AOP

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　作者：尹正杰

版权声明：原创作品，谢绝转载！否则将追究法律责任。

　　上次我分享过Spring传统的AOP编程（https://www.cnblogs.com/yinzhengjie/p/9288904.html），也知道AOP编程的其实就是动态代理模式。而本篇博客介绍的是另外一种实现AOP编程的方式，即：直接通过XML和POJO的方式实现AOP编程。

一.xml-pojo实现AOP

1>.配置Maven依赖

 <?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.org.yinzhengjie</groupId>
     <artifactId>MySpring</artifactId>
     <version>1.0-SNAPSHOT</version>

     <dependencies>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.11</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context-support</artifactId>
             <version>4.3.5.RELEASE</version>
         </dependency>
         <dependency>
             <groupId>aopalliance</groupId>
             <artifactId>aopalliance</artifactId>
             <version>1.0</version>
         </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjrt</artifactId>
             <version>1.6.1</version>
         </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjweaver</artifactId>
             <version>1.8.10</version>
         </dependency>
     </dependencies>
 </project>

2>.编写Spring的XML配置文件（aop.xml）

 <?xml version="1.0"?>
 <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"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
                         http://www.springframework.org/schema/beans/spring-beans-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/context
                         http://www.springframework.org/schema/context/spring-context-4.3.xsd
                         http://www.springframework.org/schema/tx
                         http://www.springframework.org/schema/tx ">
     <!-- 目标对象 -->
     <bean id="singer" class="cn.org.yinzhengjie.spring.aop.Singer"/>

     <!-- 观众 -->
     <bean id="audience" class="cn.org.yinzhengjie.spring.aop.Audience"/>

     <aop:config>
         <aop:aspect id="audienceAspect" ref="audience">
             <!--
                 pointcut : 表示的是切入点;
                 id : 给切入点定义一个标签，这个id的值为audiencePointcut，别人可以通过pointcut-ref属性来引用当前的pointcut切入点；
                 expression : 表示定义表达式；
                 * : 匹配返回值，表示通配符，即返回值类型不限制
                 cn.org.yinzhengjie.spring.aop.Actor.show(..) : 表示执行的方法，需要写完整类名，其中“..”表示参数不限制。
              -->
             <aop:pointcut id="audiencePointcut" expression="execution(* cn.org.yinzhengjie.spring.aop.Actor.show(..))"/>
             <!--
              before : 前置通知,表示的是在执行方法之前需要执行的代码。
              pointcut-ref : 指定切入点链接；
              method : 表示触发切入点的方法，即切入点在哪个方法中触发；
              -->
             <aop:before pointcut-ref="audiencePointcut" method="sitDown"/>
             <aop:before pointcut-ref="audiencePointcut" method="turnOffCellPhone"/>
           <!--
                 after-returning : 后置通知：主要负责处理调用目标对象之后的执行代码；
                 pointcut-ref : 指定切入点链接；
                 method : 表示触发切入点的方法，即切入点在哪个方法中触发；
           -->
             <aop:after-returning pointcut-ref="audiencePointcut" method="clap"/>
             <!--
                 after-throwing : 异常通知。它执行的优先级暂时没法确定，而且不一定执行，顾名思义，它是在有异常的时候才会触发的代码！因此即
            使你写了这样的通知，有可能你看不到它的执行结果，除非你故意写一段可能出现异常的代码；
             -->
             <aop:after-throwing pointcut-ref="audiencePointcut" method="payOff"/>
             <!--
             after : 最终通知，相当于java异常处理的fanaly代码块，无论如何都会执行的操作；
             -->
             <aop:after pointcut-ref="audiencePointcut" method="goHome"/>
         </aop:aspect>
     </aop:config>
 </beans>

3>.编写测试代码

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop;

 /**
  * 演员接口
  */
 public interface Actor {
     public void show();
 }

Actor.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop;

 /**
  * 歌手,目标类
  */
 public class Singer implements Actor {
     public void show() {
         System.out.println("I'm yinzhengjie!");
 //        String ss = null;
 //        ss.toLowerCase() ;
     }
 }

Singer.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop;

 /**
  * 观众类
  */
 public class Audience {

     public void sitDown(){
         System.out.println("sitDown");
     }
     public void turnOffCellPhone(){
         System.out.println("turnOffCellPhone");
     }
     public void clap(){
         System.out.println("clap");
     }
     public void payOff(){
         System.out.println("payOff");
     }
     public void goHome(){
         System.out.println("goHome");
     }
 }

Audience.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop;

 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 public class App {
     public static void main(String[] args) {
         //加载类的路径XMl配置文件，实例化容器。得到ApplicationContext的对象ac，我们将文件放在“resource”目录下。否则会抛异常找不到文件哟！
         ApplicationContext ac = new ClassPathXmlApplicationContext("aop.xml");
         //通过该ac的getBean方法获取到配置文件中的bean标签的指定id为"singer"的对象，由于返回的是Object对象,因此我们需要强转一下。
         Actor actor = (Actor) ac.getBean("singer");
         //调用actor对象的show方法。
         actor.show();
     }
 }

 　　以上代码执行结果如下：

二.xml-pojo实现AOP(环绕通知) 

1>.配置Maven依赖

 <?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.org.yinzhengjie</groupId>
     <artifactId>MySpring</artifactId>
     <version>1.0-SNAPSHOT</version>

     <dependencies>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.11</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context-support</artifactId>
             <version>4.3.5.RELEASE</version>
         </dependency>
         <dependency>
             <groupId>aopalliance</groupId>
             <artifactId>aopalliance</artifactId>
             <version>1.0</version>
         </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjrt</artifactId>
             <version>1.6.1</version>
         </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjweaver</artifactId>
             <version>1.8.10</version>
         </dependency>
     </dependencies>
 </project>

2>.编写Spring的XML配置文件（aop2.xml）

 <?xml version="1.0"?>
 <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"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
                         http://www.springframework.org/schema/beans/spring-beans-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/context
                         http://www.springframework.org/schema/context/spring-context-4.3.xsd
                         http://www.springframework.org/schema/tx
                         http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
     <!-- 目标对象 -->
     <bean id="singer" class="cn.org.yinzhengjie.spring.aop2.Singer" />

     <!-- 观众 -->
     <bean id="audience" class="cn.org.yinzhengjie.spring.aop2.Audience" />

     <aop:config>
         <aop:aspect id="audienceAspect" ref="audience">
             <!--
                 *  :统配返回值
                 *. :任何包以及子包
                  . :包和类的分割
                  Actor:类或者接口
                  .*  : 类或者接口中的任何方法
                  (..) : 参数不限
             -->
             <aop:around method="watch" pointcut="execution(* *..Actor.*(..))" />
         </aop:aspect>
     </aop:config>
 </beans>

3>.编写测试代码

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop2;

 /**
  * 演员接口
  */
 public interface Actor {
     public void show();
 }

Actor.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop2;

 /**
  * 歌手,目标类
  */
 public class Singer implements Actor {
     public void show() {
         System.out.println("我有一只小毛驴,从来也不骑.......");
         //模拟异常
 //        String ss = null;
 //        ss.toLowerCase() ;
     }
 }

Singer.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop2;

 import org.aspectj.lang.ProceedingJoinPoint;

 /**
  * 观众
  */
 public class Audience {

     /**
      * 观看表演
      */
     public Object watch(ProceedingJoinPoint pjp){
         try {
             System.out.println("sitDown");
             System.out.println("turnOffCellPhone");
             Object ret = pjp.proceed();
             System.out.println("clap");
             return ret ;
         } catch (Throwable e) {
             System.out.println("payOff");
         }
         finally {
             System.out.println("goHome");
         }
         return null ;
     }
 }

Audience.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.aop2;

 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 public class App {
     public static void main(String[] args) {
         ApplicationContext ac = new ClassPathXmlApplicationContext("aop2.xml");
         Actor actor = (Actor) ac.getBean("singer");
         actor.show();
     }
 }

　　以上代码执行结果如下：

三.注解方式配置spring 

　　注解是为了给类或者方法加上标记，注解是是可以通过编程提取的，它和注释可不一样哟！

1>.导入Maven依赖

 <?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.org.yinzhengjie</groupId>
     <artifactId>MySpring</artifactId>
     <version>1.0-SNAPSHOT</version>

     <dependencies>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.11</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context-support</artifactId>
             <version>4.3.5.RELEASE</version>
         </dependency>
         <dependency>
             <groupId>aopalliance</groupId>
             <artifactId>aopalliance</artifactId>
             <version>1.0</version>
         </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjrt</artifactId>
             <version>1.6.1</version>
         </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjweaver</artifactId>
             <version>1.8.10</version>
         </dependency>
     </dependencies>
 </project>

2>.编写Spring的XML配置文件（aop.xml）

 <?xml version="1.0"?>
 <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"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="http://www.springframework.org/schema/beans
                         http://www.springframework.org/schema/beans/spring-beans-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/context
                         http://www.springframework.org/schema/context/spring-context-4.3.xsd
                         http://www.springframework.org/schema/tx
                         http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
     <!-- 配置组件扫描(目的是扫描出加了注解的类或者包) -->
     <context:component-scan base-package="cn.org.yinzhengjie.spring.service" />

 </beans>

3>.编写代码

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.service;

 public interface ByeService {
     public void sayBye() ;
 }

ByeService.java 接口文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.service;

 public interface WelcomeService {
     public void sayHello() ;
 }

WelcomeService.java 接口文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.service;

 import org.springframework.stereotype.Service;

 @Service
 public class ByeServiceImpl implements ByeService{
     private String bye ;

     public ByeServiceImpl(){
         System.out.println("new ByeServiceImpl()");
     }

     public String getBye() {
         return bye;
     }

     public void setBye(String bye) {
         this.bye = bye;
     }

     public void sayBye() {
         System.out.println(bye);
     }
 }

ByeServiceImpl.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.service;

 import org.springframework.context.annotation.Scope;
 import org.springframework.stereotype.Service;

 import javax.annotation.Resource;

 @Service("yinzhengjie")             //注解是可以指定名称的，如果不指定会默认为当前类名并且首字母会小写！
 @Scope("prototype")                //指定Spring bean的范围为原型模式（"prototype"）
 public class WelcomeServiceImpl implements WelcomeService{
     private String name ;

     private ByeService bs ;
     public WelcomeServiceImpl(){
         System.out.println("new WelcomeServiceImpl()");
     }
     public ByeService getBs() {
         return bs;
     }

     //注入依赖,使用关键字name指定具体注入注解，当然也可以不在方法中注入，我们也可以在字段中注入哟！
     @Resource(name="byeServiceImpl")
     public void setBs(ByeService bs) {
         System.out.println("正在注入 : byeServiceImpl");
         this.bs = bs;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public void sayHello() {
         bs.sayBye();
         System.out.println("I'm yinzhengjie !!!");
     }
 }

WelcomeServiceImpl.java 文件内容

 /*
 @author :yinzhengjie
 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 EMAIL:y1053419035@qq.com
 */
 package cn.org.yinzhengjie.spring.service;

 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 public class App {
     public static void main(String[] args) {
         ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
         WelcomeService ws = (WelcomeService) ac.getBean("yinzhengjie");
         ws.sayHello();
         ByeService bs = (ByeService) ac.getBean("byeServiceImpl");
         System.out.println(bs);

     }
 }

　　以上代码执行结果如下：