1 package soundsystem;
 2 import org.springframework.context.annotation.ComponentScan;
 3 import org.springframework.context.annotation.Configuration;
 4
 5 @Configuration    //说明此类是配置文件
 6 //@ComponentScan //开启扫描，会扫描当前类的包及其子包
 7 //@ComponentScan(basePackages={"soundsystem", "video"})//扫描多个包
 8 @ComponentScan(basePackageClasses={CDPlayer.class})//指定要扫描的类
 9 public class CDPlayerConfig {
10 }

 1 package soundsystem;
 2 import org.springframework.beans.factory.annotation.Autowired;
 3 import org.springframework.stereotype.Component;
 4
 5 @Component
 6 public class CDPlayer implements MediaPlayer {
 7   private CompactDisc cd;
 8
 9   @Autowired
10   public CDPlayer(CompactDisc cd) {  //依赖bean的id会叫"cd"???
11     this.cd = cd;
12   }
13
14   public void play() {
15     cd.play();
16   }
17
18 }

 1 package soundsystem;
 2 import org.springframework.stereotype.Component;
 3
 4 @Component
 5 public class SgtPeppers implements CompactDisc {
 6
 7   private String title = "Sgt. Pepper's Lonely Hearts Club Band";
 8   private String artist = "The Beatles";
 9
10   public void play() {
11     System.out.println("Playing " + title + " by " + artist);
12   }
13
14 }

 1 package soundsystem;
 2
 3 import static org.junit.Assert.*;
 4
 5 import org.junit.Rule;
 6 import org.junit.Test;
 7 import org.junit.contrib.java.lang.system.StandardOutputStreamLog;
 8 import org.junit.runner.RunWith;
 9 import org.springframework.beans.factory.annotation.Autowired;
10 import org.springframework.test.context.ContextConfiguration;
11 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
12
13 @RunWith(SpringJUnit4ClassRunner.class)    //会自动创建applicationcontext
14 @ContextConfiguration(classes=CDPlayerConfig.class)//指定配置文件
15 public class CDPlayerTest {
16
17   @Rule
18   public final StandardOutputStreamLog log = new StandardOutputStreamLog();
19
20   @Autowired
21   private MediaPlayer player;  //默认id会是“player”???
22
23   @Autowired
24   private CompactDisc cd;
25
26   @Test
27   public void cdShouldNotBeNull() {
28     assertNotNull(cd);
29   }
30
31   @Test
32   public void play() {
33     player.play();
34     assertEquals(
35         "Playing Sgt. Pepper's Lonely Hearts Club Band by The Beatles",
36         log.getLog());
37   }
38
39 }