Unsatisfied dependency expressed through field 'userRepository'

Question

Can't solve problems with test Spring Boot application:

spring.bat init --artifactId=dbproto3 --boot-version=2.1.7.RELEASE --dependencies=jdbc,data-rest,web,thymeleaf,devtools,lombok,configuration-processor,security,data-jpa,data-jdbc,postgresql,actuator --description=dbproto3 --groupId=com.test --java-version=11 --name=dbproto3 --package-name=com.test.dbproto3 --version=0.0.1-SNAPSHOT

It is a test application made by modifying Guide "Accessing data with MySQL" from official Spring site. The first version (close to initial: empty springconfig, @Controller and @RequestMapping(path="/demo"), ...) worked great but my version generates an exception

Running it i get an exception:

Exception in thread "restartedMain" java.lang.reflect.InvocationTargetException
  2 .   at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  3 .   at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  4 .   at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  5 .   at java.base/java.lang.reflect.Method.invoke(Method.java:566)
  6 .   at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
  7 . Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mainController': Unsatisfied dependency expressed through field 'userRepository'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.test.dbproto3.UserRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
  8 .   at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596)
  9 .   at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
 10 .   at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374)
 11 .   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1411)
 12 .   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592)
 13 .   at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
 14 .   at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
 15 .   at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
 16 .   at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
 17 .   at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
 18 .   at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:845)
 19 .   at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:877)
 20 .   at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549)
 21 .   at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:88)
 22 .   at com.test.dbproto3.Dbproto3Application.main(Dbproto3Application.java:18)
 23 .   ... 5 more
 24 . Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.test.dbproto3.UserRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
 25 .   at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1658)
 26 .   at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1217)
 27 .   at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1171)
 28 .   at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593)
 29 .   ... 19 more

Dbproto3Application:

@SpringBootApplication
  2 . public class Dbproto3Application {
  3 .
  4 .    public static void main(String[] args) {
  5 .         SpringApplication.run(Dbproto3Application.class, args);
  6 .
  7 .         ApplicationContext javaConfigContext = new AnnotationConfigApplicationContext(SpringConfig.class);
  8 .
  9 .         MainController mainControllerObj = (MainController) javaConfigContext.getBean("mainController");
 10 .
 11 .         mainControllerObj.addNewUser();
 12 .    }
 13 . }

SpringConfig:

  1 . @Configuration
  2 . public class SpringConfig {
  3 .     @Bean("mainController")
  4 .     public MainController createMainController() {
  5 .         return new MainController();
  6 .     }
  7 . }

User:

 1 . @Entity
  2 . @Table(name = "userstab")
  3 . public class User {
  4 .   @Id
  5 .   @GeneratedValue(strategy=GenerationType.AUTO)
  6 .   private Integer id;
  7 .
  8 .   private String name;
  9 .
 10 .   private String email;
 11 .
 12 . }

UserRepository:

  1 . public interface UserRepository extends CrudRepository<User, Integer> {
  2 .
  3 . }

MainController:

  3 . public class MainController {
  4 .
  5 .     @Autowired
  6 .     private UserRepository userRepository;
  7 .
  8 .
  9 .     public void addNewUser() {
 10 .         User n = new User();
 11 .         n.setName("testuser");
 12 .         n.setEmail("testemail");
 13 .         System.out.println("addNewUser()");
 14 .         userRepository.save(n);
 15 .     }
 16 .
 17 . }

application properties:

server.port = 8082

## default connection pool
spring.datasource.hikari.connectionTimeout=20000
spring.datasource.hikari.maximumPoolSize=5


## PostgreSQL
spring.datasource.url=jdbc:postgresql://localhost:5432/example_db
spring.datasource.username=someuser
spring.datasource.password=123456

spring.jpa.hibernate.ddl-auto=update

Answer 1

I could not see any annotations for your repository interface in the code that you shared .Even though you are extending the CrudRepository interface to create your own interface. Spring boot needs to understand during startup that it needs to provide default implementation for your entities.Use annotation @Repository on your interface like :

 @Repository
 public interface UserRepository extends CrudRepository<User, Integer> {
  
  }

Also, you are creating the controller bean in some weird way , so you might be attempting something unconventional which means just using @Autowired in your main application class might also be a bit of stretch for you. But i would suggest doing that. You are using AnnotationConfigApplicationContext to create the bean for your controller but you are only providing the configuration class that you created for scanning. Maybe the bean for UserRepository since it's getting created by springboot is not present in the application context that you created using AnnotationConfigApplicationContext. I think it's a standalone context.