笔记11 在XML中声明切面（2）

2023-07-27 11:16:34

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

码农公寓

相关文章