自动装配：期望至少有1个bean符合此依赖项的自动装配候选条件

Question

好的，我知道围绕同一主题有很多问题。但我似乎无法使任何工作。我可能还没有完全理解自动接线概念。我的问题：我能够到达所需的页面，但是每当我单击any按钮执行操作时，我都会得到Null指针异常，这似乎很明显，因为我认为spring无法正确映射所需的bean。

因此，当我添加@ autowired = true时，它给了我以上给出的异常。我不确定该怎么做。希望有人可以帮助我。还要解释一下：）代码：

@Entity
@Table(name="userDetails")
public class UserDetailModel {

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public int user_id;
public String password;
public String user_name;
public String active_status;

public String getPassword() {
    return password;
}

public void setPassword(String password) {
    this.password = password;
}

public String getUser_name() {
    return user_name;
}

public void setUser_name(String user_name) {
    this.user_name = user_name;
}

public int getUser_id() {
    return user_id;
}

public void setUser_id(int user_id) {
    this.user_id = user_id;
}

public String getActive_status() {
    return active_status;
}

public void setActive_status(String active_status) {
    this.active_status = active_status;
}

}

控制器：

@RestController
public class UserDetailController {

 private Logger logger = (Logger) LoggerFactory.getLogger(UserDetailController.class);
 @Autowired(required = true)
private UserRepository userRepository;

@RequestMapping(value="/login", method = RequestMethod.POST)
public @ResponseBody String addNewUser (@RequestBody UserDetailModel user) {
    // @ResponseBody means the returned String is the response, not a view name
    // @RequestParam means it is a parameter from the GET or POST request

    logger.debug("in controller");
    UserDetailModel userDtl = new UserDetailModel();
    userDtl.setUser_id(user.user_id);
    userDtl.setUser_name(user.user_name);
    userDtl.setActive_status(user.active_status);
    userDtl.setPassword(user.password);

    userRepository.save(userDtl);
    return "Saved";
}

}

仓库：

@Repository
public interface UserRepository extends CrudRepository<UserDetailModel,         Long> {}

堆栈跟踪：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userDetailController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.springBoot.usl.repo.UserRepository com.springBoot.usl.controller.UserDetailController.userRepository; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.springBoot.usl.repo.UserRepository] 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:292)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:703)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:120)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:683)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:313)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:944)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:933)
at com.springBoot.usl.controller.WebAppInitializer.main(WebAppInitializer.java:18)

根据 回答解决：回答： 我根据杰伊和路易的回答做了一些修改。并在我的ApplicationConfig文件中按如下所示更改批注：

@Configuration
@ComponentScan("my.basepackage.*")
@EnableJpaRepositories(basePackages = {"my.basepackage.*"})
@EntityScan("my.basepackage.*")
@EnableAutoConfiguration

希望这可以帮助一些人。

但是我不确定*是否是正确的方法。

Answer 1

我可以在注释方面进行一些更改来运行您的应用程序。

我使用了有问题的相同的类。请参见下面使用的结构和配置。 目录结构

我使用了以下软件包，并添加了您的类
com.rcmutha.usl.controller
com.rcmutha.usl.repository

@SpringBootApplication
@ComponentScan({"com.rcmutha*"})
@EntityScan("com.rcmutha*")
@EnableJpaRepositories("com.rcmutha*")
public class Application {

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

完整的代码： 单击此处获取代码

Answer 2

您需要在配置类中启用 JPA 存储库，指定包含存储库的包，如下所示

@Configuration
@EnableJpaRepositories(basePackages = {
    "com.springBoot.usl.repo"
})
public class ApplicationConfig {

}

应用程序配置示例：

@Configuration
@EnableJpaRepositories(basePackages = {"com.springBoot.usl.repo"})
@EnableTransactionManagement
public class ApplicationConfig {

    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/xxxx");
        dataSource.setUsername("xxxx");
        dataSource.setPassword("xxxx");

        return dataSource;
    }

    @Bean
    public EntityManagerFactory entityManagerFactory() {
        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(true);
        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(vendorAdapter);
        factory.setPackagesToScan("xx.xxxx.xxxx.xxxx.domain");
        factory.setDataSource(dataSource());
        factory.afterPropertiesSet();
        return factory.getObject();
    }

    @Bean
    public PlatformTransactionManager transactionManager() {
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory());
        return txManager;
    }