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 - 1));
    }

    @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 + 1);
    }

    public int getPlayCount(int trackNumber) {
        return trackCounts.containsKey(trackNumber) ? trackCounts.get(trackNumber) : 0;
    }
} 

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>9999999999</value>
                <value>8888888888</value>
                <value>7777777777</value>
                <value>6666666666</value>
                <value>5555555555</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(1);
        cd.playTrack(2);
        cd.playTrack(2);
        cd.playTrack(3);
        cd.playTrack(3);
        cd.playTrack(3);
        cd.playTrack(4);
        cd.playTrack(4);
        cd.playTrack(4);
        cd.playTrack(5);
        cd.playTrack(5);
        for (int i = 1; i < 6; 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