org.springframework.beans.factory.UnsatisfiedDependencyException:使用名称' demoRestController'

时间:2016-05-13 16:01:16

标签: java dependency-injection spring-boot

我是Spring的新手,我正在尝试创建一个学习应用程序,但我在自动装配中遇到问题,我正在添加我的代码。我正在弹簧靴。

Spring Boot Code

public class DemoApplication {

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

LoginBean.java

@Service
@Component
public class LoginBean {
    private String userId;
    private String pwd;

    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

DemoRestController.java

@RestController
@EnableAutoConfiguration
@RequestMapping("/demo")
@Component
public class DemoRestController {


    private final LoginBean loginBean;

    @Autowired
    public DemoRestController(LoginBean loginBean) {
        this.loginBean=loginBean;
    }

    @RequestMapping(value = "/login/{id},{pwd}", method = RequestMethod.GET, produces = "application/json")
    public @ResponseBody LoginBean loginService(@PathVariable String id, @PathVariable String pwd) {
        //LoginBean loginBean = new LoginBean();

        loginBean.setUserId(id);
        loginBean.setPwd(pwd);
        return loginBean;
    }

我尝试了以下方案来使我的@Autowired工作:

  1. @Autowired to LoginBean loginBean;
  2. 在Controller类和自动装配的setter中创建了LoginBean的getter setter;
  3. 创建Controller的构造函数并自动装配,如上面的代码所示;
  4. 以下是我得到的错误

    org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demoRestController': Unsatisfied dependency expressed through constructor argument with index 0 of type [com.ag.digital.demo.bean.LoginBean]: No qualifying bean of type [com.ag.digital.demo.bean.LoginBean] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.ag.digital.demo.bean.LoginBean] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:185) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
        at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
        at com.ag.digital.demo.boot.DemoApplication.main(DemoApplication.java:14) [classes/:na]
    Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.ag.digital.demo.bean.LoginBean] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1373) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1119) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:813) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
        ... 19 common frames omitted
    

2 个答案:

答案 0 :(得分:32)

您的DemoApplication课程位于com.ag.digital.demo.boot包中,而您的LoginBean课程位于com.ag.digital.demo.bean包中。默认情况下,如果它们位于主应用程序类@Component的同一个包或子包中,则会找到组件(使用DemoApplication注释的类)。这意味着LoginBean未被发现,因此依赖注入失败。

有几种方法可以解决您的问题:

  1. LoginBean移至com.ag.digital.demo.boot或子包中。
  2. 使用应scanBasePackages上的@SpringBootApplication DemoApplication属性配置扫描组件的软件包。
  3. 其他一些不会导致问题的事情,但对于您发布的代码并不完全正确:

    • @Service@Component的专精,因此您不需要LoginBean
    • 同样,@RestController@Component的专精,因此您不需要DemoRestController
    • DemoRestController@EnableAutoConfiguration不寻常的地方。该注释通常可以直接或通过DemoApplication @SpringBootApplication@ComponentScan@Configuration的{​​{1}}在主应用类(@EnableAutoConfiguration)上找到。

答案 1 :(得分:0)

对我来说,发生在DogController中,它自动连接了DogService,然后又自动连接了DogRepositoryDog类曾经具有字段name,但我将其更改为coolName,但没有更改DogRepositoryDog findDogByName(String name)中的方法。我将该方法更改为Dog findDogByCoolName(String name),现在可以使用了。