Spring JPA 数据存储库无法为扩展 CrudRepository 的接口创建 bean

Question

我在使用 Spring JPA 存储库时遇到问题。我创建了：

一个基本用户域class (@Entity),
一个接口 UserDao 扩展了 CrudRepository
和服务层实现。

当我运行项目时，由于UserDao的bean创建异常而失败。据我所知，Spring JPA 存储库有责任为此接口创建 bean（因为它扩展了 CrudRepository）并将其注入到需要的地方。

这是我遇到的错误：

WARN : org.springframework.web.context.support.AnnotationConfigWebApplicationContext - Exception encountered during context initialization - cancelling refresh attempt org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'UserController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private edu.sjsu.services.UserService edu.sjsu.controllers.UserController.userService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userServiceImpl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: edu.sjsu.models.UserDao edu.sjsu.services.UserServiceImpl.userDao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [edu.sjsu.models.UserDao] 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)

UserDao.Java:

package edu.sjsu.models;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.CrudRepository;

public interface UserDao extends CrudRepository<User, Long> {}

RootConfig.Java:

@Configuration
@ComponentScan(basePackages={"edu.sjsu"}, excludeFilters={@Filter(type=FilterType.ANNOTATION, value=EnableWebMvc.class)})
@Import(JpaConfig.class)
public class RootConfig {}

JpaConfig.java 我认为如果使用 Spring JPA 我什至不需要这个，但我仍然按照指南和教程创建了这个配置 class。

@Configuration
@EnableJpaRepositories
@EnableTransactionManagement
public class JpaConfig {

    @Bean
    public DataSource dataSource() {
        EmbeddedDatabaseBuilder builder = new EmbeddedDatabaseBuilder();
        return builder.setType(EmbeddedDatabaseType.HSQL).build();
    }

    @Bean
    public EntityManagerFactory entityManagerFactory() {

        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(true);

        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(vendorAdapter);
        factory.setPackagesToScan("edu.sjsu");
        factory.setDataSource(dataSource());
        factory.afterPropertiesSet();

        return factory.getObject();
    }

    @Bean
    public PlatformTransactionManager transactionManager() {

        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory());
        return txManager;
    }   

}

如果您需要其他配置和 java class 了解情况，请告诉我。

Answer 1

在EnableJpaRepositories中使用basePackages:

@Configuration
@EnableJpaRepositories(basePackages = "edu.sjsu.models")
@EnableTransactionManagement
public class JpaConfig { ... }

默认情况下，EnableJpaRepositories 将为 Spring 个数据存储库扫描注释配置 class 的包。因为，我猜，你的配置和存储库 classes 在不同的包中，你应该告诉 Spring Data JPA 要扫描哪个基础包以找到 JPA 存储库。

Spring JPA 数据存储库无法为扩展 CrudRepository 的接口创建 bean

Spring JPA Data Repository failed to create bean for interface that extends CrudRepository

java

spring

hibernate

spring-data

spring-data-jpa