无法在Spring启动时自动装配DAO

时间：2016-10-18 12:43:05

标签： hibernate spring-boot repository autowired

我的应用程序位于 in.orgname.projectname.backend 

@SpringBootApplication
public class Application {

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

我的道在 in.orgname.projectname.backend.model.dao 

public interface MyUserDao extends CrudRepository<MyUser, String>{

    public MyUser findByEmailId(String emailId);
}

我的实体位于 in.orgname.projectname.backend.model.entity

最后尝试在 in.orgname.projectname.backend.controllers

中的Controller中访问此DAO 
@RestController
public class AuthenticationController {

    @Autowired
    MyUserDao myUserDao;

    @RequestMapping(value = "/authenticate", method = RequestMethod.POST)
    public ResponseEntity<String> authenticate(@RequestParam(value = "authcode") String authCode){

        //Some other code
    }

}

我收到此错误：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'authenticationController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.orgname.projectname.backend.model.dao.MyUserDao in.orgname.projectname.backend.controllers.AuthenticationController.myUserDao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.orgname.projectname.backend.model.dao.MyUserDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.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-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
    at in.orgname.projectname.backend.Application.main(Application.java:11) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.orgname.projectname.backend.model.dao.MyUserDao in.orgname.projectname.backend.controllers.AuthenticationController.myUserDao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.orgname.projectname.backend.model.dao.MyUserDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    ... 17 common frames omitted
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.orgname.projectname.backend.model.dao.MyUserDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1373) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1119) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]
    ... 19 common frames omitted

我经历过StackOverflow上的各种来源，但似乎没有解决我的问题。

我该如何处理？

EDIT1：我也直接在DAO课上试过@Component。

EDIT2：以下是项目的git存储库，它有相同的错误 - https://github.com/amitection/myuser-poc

3 个答案:

答案 0 :(得分：1)

根据示例应用程序，问题是您没有将postgresql库作为依赖项。如果没有，Spring就不会自动提供由postgres支持的Repository bean。

您需要添加：

    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
    </dependency>

Spring Boot Autoconfiguration仅在检测到类路径上的特定类时才加载bean。一旦它在类路径上看到postgresql，它就会尝试生成Repository bean。

答案 1 :(得分：0)

您需要在servlet.xml中设置扫描<context:component-scan base-package="com.example" />以进行自动引用，或者在Spring Boot中将@ComponentScan添加到Application类。

答案 2 :(得分：0)

  1. 添加此依赖项
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.2</version>
    </dependency>
  1. 然后将@MapperScan添加到入门级课程
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