@Autowired在spring项目中失败

Question

我有一个简单的Spring项目，就在一个模板上：

@SpringBootApplication
@RestController
public class HelloWorldRestApplication {

public static void main(String[] args) {
    SpringApplication.run(HelloWorldRestApplication.class, args);

    Performer p = new Performer();
    p.perform();
    }
}

我有一个确保自动装配工作的测试，实际上它在这个测试类中是这样做的(示例来自Spring in Action，4)：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes=CDPlayerConfig.class)
public class CDPlayerTest {

@Autowired
private CDPlayer cdp;

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

以及：

public class Performer {

@Autowired
private CDPlayer cdp;

public void perform(){
    System.out.println(cdp);
    cdp.play();
}

public CDPlayer getCdp() {
    return cdp;
}

public void setCdp(CDPlayer cdp) {
    this.cdp = cdp;
}
}

以及：

@Component
public class CDPlayer{

public void play(){
     System.out.println("play");
  }
}

配置：

 @Configuration
 @ComponentScan
 public class CDPlayerConfig {

 }

但是，它在HelloWorldRestApplication中不起作用，我得到null。

添加@ContextConfiguration(classes=CDPlayerConfig.class)是没有帮助的。

我错过了什么？

Answer 1

尝试在主类中启用@ComponentScan包，并从ApplicationContext获取Performer类实例，如下所示：

@SpringBootApplication
@RestController
@ComponentScan({“package.name.1”,”package.name.2”})
public class HelloWorldRestApplication {

public static void main(String[] args) {
    ApplicationContext ctx = SpringApplication.run(HelloWorldRestApplication.class, args);

    Performer p = ctx.getBean(Performer.class);//get the bean by type                      
    p.perform();
    }
}