笔记11 在XML中声明切面（2）

为通知传递参数

1.声明一个CompactDiscs接口。内部包含两个方法：

• • show()　　用于显示唱片的名字和艺术风格
  • playTrack(int number)　　根据传入的磁道数播放相应磁道的音乐（假设每个磁道就一首歌）

 package XMLsoundsystem;

 public interface CompactDiscs {
     void show();

     void playTrack(int number);
 }

2.实现接口的类BlankDisc

 package XMLsoundsystem;

 import java.util.List;

 public class BlankDisc implements CompactDiscs {
     private String title;
     private String artist;
     private List<String> tracks;

     public String getTitle() {
         return title;
     }

     public void setTitle(String title) {
         this.title = title;
     }

     public String getArtist() {
         return artist;
     }

     public void setArtist(String artist) {
         this.artist = artist;
     }

     public List<String> getTracks() {
         return tracks;
     }

     public void setTracks(List<String> tracks) {
         this.tracks = tracks;
     }

     @Override
     public void playTrack(int number) {
         System.out.println(tracks.get(number - ));
     }

     @Override
     public void show() {
         System.out.println("唱片的名字：" + title);
         System.out.println("唱片属于的艺术流派：" + artist);
     }

 } 

3.无注解的TrackCounter，用来记录播放的次数。

 package XMLsoundsystem;

 import java.util.HashMap;
 import java.util.Map;

 public class TrackCounter {
     private Map<Integer, Integer> trackCounts = new HashMap<Integer, Integer>();

     public void countTrack(int trackNumber) {
         int currentCount = getPlayCount(trackNumber);
         trackCounts.put(trackNumber, currentCount + );
     }

     public int getPlayCount(int trackNumber) {
         return trackCounts.containsKey(trackNumber) ? trackCounts.get(trackNumber) : ;
     }
 } 

4.XML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"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:c="http://www.springframework.org/schema/c"
     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/tx
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">
     <bean id="trackCounter" class="XMLsoundsystem.TrackCounter"></bean>
     <bean id="cd" class="XMLsoundsystem.BlankDisc">
         <property name="title" value="AAAAABBBBCCCC"></property>
         <property name="artist" value="CCCCCBBBBBAAAA"></property>
         <property name="tracks">
             <list>
                 <value></value>
                 <value></value>
                 <value></value>
                 <value></value>
                 <value></value>
             </list>
         </property>
     </bean>
      <aop:config>
          <aop:aspect ref="trackCounter">
              <aop:pointcut expression="execution(* XMLsoundsystem.CompactDiscs.playTrack(int)) and args(trackNumber)" id="trackPlayed"/>
              <aop:before pointcut-ref="trackPlayed" method="countTrack"/>
          </aop:aspect>
      </aop:config>
    </beans>

5.测试

 package XMLsoundsystem;

 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration("classpath:ConcertConfig4.xml")
 public class TrackCounterTest {
     @Autowired
     private CompactDiscs cd;
     @Autowired
     private TrackCounter counter;

     @Test
     public void test() {
         cd.show();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         cd.playTrack();
         for (int i = ; i < ; i++) {
             System.out.println("磁道" + i + "播放了" + counter.getPlayCount(i) + "次");
         }
     }
 } 

6.结果

通过切面引入新的功能

1.定义表演接口Performance.java

 package concert3;

 public interface Performance {
     public void perform();
 }

2.实现接口，Classcial.java

 package concert3;

 public class Classcial implements Performance {

     @Override
     public void perform() {
         // TODO Auto-generated method stub
         System.out.println("我是古典音乐会！");
     }

 }

3.定义观众类，即切面 Audience.java

 package concert3;

 import org.aspectj.lang.ProceedingJoinPoint;

 public class Audience {

     // ProceedingJoinPoint作为参数。
     // 这个对象是必须要有的，因为 你要在通知中通过它来调用被通知的方法。
     // 通知方法中可以做任何的 事情，当要将控制权交给被通知的方法时，它需要调 用ProceedingJoinPoint的proceed()方法。
     public void watchPerformance(ProceedingJoinPoint jp) {
         try {
             System.out.println("Silencing cell phone");
             System.out.println("Taking seats");
             jp.proceed();
             System.out.println("CLAP CLAP CLAP");
         } catch (Throwable e) {
             System.out.println("Demanding a refund");
         }
     }
 }

4.定义新功能接口 Encoreable.java

 package concert3;

 public interface Encoreable {
     void performEncore();
 }

5.实现新接口DefaultEncoreable.java

 package concert3;

 public class DefaultEncoreable implements Encoreable {

     @Override
     public void performEncore() {
         // TODO Auto-generated method stub
         System.out.println("川剧变脸");
     }

 }

6.XML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"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xmlns:tx="http://www.springframework.org/schema/tx"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:c="http://www.springframework.org/schema/c"
     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/tx
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

            <bean class="concert3.Classcial"></bean>
            <bean id="audience" class="concert3.Audience"></bean>
            <aop:config>
                    <aop:aspect ref="audience">
                        <aop:pointcut expression="execution(* concert3.Performance.perform(..))" id="performance"/>
                        <aop:around method="watchPerformance" pointcut-ref="performance"/>
                        <aop:declare-parents types-matching="concert3.Performance+"
                                             implement-interface="concert3.Encoreable"
                                             default-impl="concert3.DefaultEncoreable"/>
                    </aop:aspect>
            </aop:config>
    </beans>

7.测试

 package concert3;

 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

 @RunWith(SpringJUnit4ClassRunner.class)
 // @ContextConfiguration(classes = concert3.ConcertConfig.class)
 @ContextConfiguration("classpath:ConcertConfig5.xml")
 public class ConcertTest {
     @Autowired
     public Performance p;
     @Autowired
     public Encoreable en;

     @Test
     public void test() {

         p.perform();
         System.out.println("-----------------------------");
         System.out.println("自己创建对象调用");
         en.performEncore();
         System.out.println("-----------------------------");
         System.out.println("通过Performance对象调用“新方法”");
         Encoreable e = (Encoreable) p;
         e.performEncore();
     }
 }

8.结果