SPRING IN ACTION 第4版笔记-第二章-001-用@Autowired\@ComponentScan、@Configuration、@Component实现自动装载bean

1.

 package soundsystem;
 import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;

 @Configuration    //说明此类是配置文件
 //@ComponentScan //开启扫描，会扫描当前类的包及其子包
 //@ComponentScan(basePackages={"soundsystem", "video"})//扫描多个包
 @ComponentScan(basePackageClasses={CDPlayer.class})//指定要扫描的类
 public class CDPlayerConfig {
 }

2.

 package soundsystem;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;

 @Component
 public class CDPlayer implements MediaPlayer {
   private CompactDisc cd;

   @Autowired
   public CDPlayer(CompactDisc cd) {  //依赖bean的id会叫"cd"???
     this.cd = cd;
   }

   public void play() {
     cd.play();
   }

 }

3.

 package soundsystem;
 import org.springframework.stereotype.Component;

 @Component
 public class SgtPeppers implements CompactDisc {

   private String title = "Sgt. Pepper's Lonely Hearts Club Band";
   private String artist = "The Beatles";

   public void play() {
     System.out.println("Playing " + title + " by " + artist);
   }

 }

4.

 package soundsystem;

 import static org.junit.Assert.*;

 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.contrib.java.lang.system.StandardOutputStreamLog;
 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)    //会自动创建applicationcontext
 @ContextConfiguration(classes=CDPlayerConfig.class)//指定配置文件
 public class CDPlayerTest {

   @Rule
   public final StandardOutputStreamLog log = new StandardOutputStreamLog();

   @Autowired
   private MediaPlayer player;  //默认id会是“player”???

   @Autowired
   private CompactDisc cd;

   @Test
   public void cdShouldNotBeNull() {
     assertNotNull(cd);
   }

   @Test
   public void play() {
     player.play();
     assertEquals(
         "Playing Sgt. Pepper's Lonely Hearts Club Band by The Beatles",
         log.getLog());
   }

 }

bean