自动assembly：预计至少有一个bean可以作为此依赖关系的autowire候选者
好的，我知道围绕同一主题提出了很多问题。 但我似乎无法做任何事情。 也可能是我还没有完全理解汽车接线概念。 我的问题：我能够到达所需的页面，但每当我点击任何按钮执行操作时，我都会得到Null指针exception，这似乎很明显，因为我不认为spring能够正确映射所需的bean。
所以，当我添加@ autowired = true时，它会给我上面给出的例外情况。 我不确定需要做什么。希望有人可以帮我解决这个问题。 也会喜欢一个解释:)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"; }
}
库：
@Repository public interface UserRepository extends CrudRepository {}
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 答案：我根据Jay和Luay的答案做了一些修改。 并在我的ApplicationConfig文件中更改了注释：
@Configuration @ComponentScan("my.basepackage.*") @EnableJpaRepositories(basePackages = {"my.basepackage.*"}) @EntityScan("my.basepackage.*") @EnableAutoConfiguration
希望这对某人有所帮助。
但我不确定*是否是正确的方法。
我可以在注释端进行一些更改来运行您的应用程序。
我使用了相同的课程。 请参阅下面使用的结构和配置。 目录结构
我使用了如下的包，并添加了你的课程，
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); } }
完整代码： 点击此处查看代码
我认为您的应用程序无法扫描UserRepository类，如果您使用的是Spring Boot，那么您应该将主类放在包层次结构的顶部。
您还应该使用@EnableJpaRepositories并告诉它您的repos的基本包以启用存储库function
@EnableJpaRepositories(basePackages ={"com.springBoot.usl.repo"})
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 { }
ApplicationConfig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; }
UserRepository根本没有在当前的Spring Context中定义。 确保您的类在Spring扫描的包中定义。 您需要在Configuration类中使用@ComponentScan("org.my.pkg")来使Spring扫描包。
如果您正在使用Spring Boot，请确保在其他类之上的根包中找到使用@SpringBootApplication注释的主应用程序类，因为它包含@ComponentScan 。