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();
}

/*
@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() ;
    }
}

/*
@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");
    }
}

/*
@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();
}

/*
@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() ;
    }
}

/*
@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 ;
    }
}

/*
@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() ;
}

/*
@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() ;
}

/*
@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);
    }
}

/*
@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 !!!");
    }
}

/*
@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：