Question

我正在创建一个REST服务来在mongodb上进行通信和执行基本的CRUD操作。但我接收到以下错误：

Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mongoDBTodoService' defined in file [/Users/avarshney/Documents/Aayush/STS/rest_mongo/target/classes/rest_mongo/MongoDBTodoService.class]: Unsatisfied dependency expressed through constructor argument with index 0 of type [rest_mongo.TodoRepository]: : No qualifying bean of type [rest_mongo.TodoRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [rest_mongo.TodoRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749)
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:185)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1131)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1034)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:686)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:957)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:946)
at rest_mongo.TodoAppConfig.main(TodoAppConfig.java:14)

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [rest_mongo.TodoRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1301)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1047)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:942)
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:813)
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741)

以下是我各自的课程：

TodoAppConfig.java

package rest_mongo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class TodoAppConfig {

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

TodoService.java （接口）

package rest_mongo;

import java.util.List;

interface TodoService {

    TodoDTO create(TodoDTO todo);

    TodoDTO delete(String id);

    List<TodoDTO> findAll();

    TodoDTO findById(String id);

    TodoDTO update(TodoDTO todo);
}

TodoRepository.java （接口）

package rest_mongo;

import org.springframework.data.repository.Repository;

import java.util.List;

interface TodoRepository extends Repository<Todo, String> {

    void delete(Todo deleted);

    List<Todo> findAll();

    Todo findOne(String id);

    Todo save(Todo saved);
}

TodoDTO.java

package rest_mongo;

import org.hibernate.validator.constraints.NotEmpty;

import javax.validation.constraints.Size;

public final class TodoDTO {

    private String id;

    @Size(max = Todo.MAX_LENGTH_DESCRIPTION)
    private String description;

    @NotEmpty
    @Size(max = Todo.MAX_LENGTH_TITLE)
    private String title;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }


}

TodoController.java

package rest_mongo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;
import java.util.List;

@RestController
@RequestMapping("/Users/avarshney/Documents/Aayush/STS/rest_mongo/target/classes/rest_mongo/todo")
final class TodoController {

    private final TodoService service;

    @Autowired
    TodoController(TodoService service) {
        this.service = service;
    }

    @RequestMapping(method = RequestMethod.POST)
    @ResponseStatus(HttpStatus.CREATED)
    TodoDTO create(@RequestBody @Valid TodoDTO todoEntry) {
        return service.create(todoEntry);
    }

    @RequestMapping(value = "{id}", method = RequestMethod.DELETE)
    TodoDTO delete(@PathVariable("id") String id) {
        return service.delete(id);
    }

    @RequestMapping(method = RequestMethod.GET)
    List<TodoDTO> findAll() {
        return service.findAll();
    }

    @RequestMapping(value = "{id}", method = RequestMethod.GET)
    TodoDTO findById(@PathVariable("id") String id) {
        return service.findById(id);
    }

    @RequestMapping(value = "{id}", method = RequestMethod.PUT)
    TodoDTO update(@RequestBody @Valid TodoDTO todoEntry) {
        return service.update(todoEntry);
    }

}

Todo.java

package rest_mongo;

import org.springframework.data.annotation.Id;

final class Todo
{
    static final int MAX_LENGTH_DESCRIPTION = 500;
    static final int MAX_LENGTH_TITLE = 100;

    @Id
    private String id;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    private String description;

    private String title;

    public Todo() {}

    private Todo(Builder builder) {
        this.description = builder.description;
        this.title = builder.title;
    }

    static Builder getBuilder() {
        return new Builder();
    }

    //Other getters are omitted

    public void update(String title, String description) {
        this.title = title;
        this.description = description;
    }

    static class Builder {

        private String description;

        private String title;

        private Builder() {}

        Builder description(String description) {
            this.description = description;
            return this;
        }

        Builder title(String title) {
            this.title = title;
            return this;
        }

        Todo build() {
            Todo build = new Todo(this);

            return build;
        }
    }
}

MongoDBTodoService.java

package rest_mongo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

import static java.util.stream.Collectors.toList;

@Service
final class MongoDBTodoService implements TodoService {

    @Autowired
    private final TodoRepository repository;

    @Autowired
    MongoDBTodoService(TodoRepository repository) {
        this.repository = repository;
    }

    @Override
    public TodoDTO create(TodoDTO todo) {
        Todo persisted = Todo.getBuilder()
                .title(todo.getTitle())
                .description(todo.getDescription())
                .build();
        persisted = repository.save(persisted);
        return convertToDTO(persisted);
    }

    @Override
    public TodoDTO delete(String id) {
        Todo deleted = findTodoById(id);
        repository.delete(deleted);
        return convertToDTO(deleted);
    }

    @Override
    public List<TodoDTO> findAll() {
        List<Todo> todoEntries = repository.findAll();
        return convertToDTOs(todoEntries);
    }

    private List<TodoDTO> convertToDTOs(List<Todo> models) {
        return models.stream()
                .map(this::convertToDTO)
                .collect(toList());
    }

    @Override
    public TodoDTO findById(String id) {
        Todo found = findTodoById(id);
        return convertToDTO(found);
    }

    @Override
    public TodoDTO update(TodoDTO todo) {
        Todo updated = findTodoById(todo.getId());
        updated.update(todo.getTitle(), todo.getDescription());
        updated = repository.save(updated);
        return convertToDTO(updated);
    } 

    private Todo findTodoById(String id) {
        Todo result = repository.findOne(id);
        return result;

    }

    private TodoDTO convertToDTO(Todo model) {
        TodoDTO dto = new TodoDTO();

        dto.setId(model.getId());
        dto.setTitle(model.getTitle());
        dto.setDescription(model.getDescription());

        return dto;
    }
}

我对这项技术很陌生，所以请告诉我是否有一些非常明显的错误。我指的是此代码的此链接：http://www.petrikainulainen.net/programming/spring-framework/creating-a-rest-api-with-spring-boot-and-mongodb/

请告诉我如何解决此错误。

Answer 1

来自文档

Spring Data可以为您创建@Repository的实现各种口味的界面。 Spring Boot将处理所有这些只要那些@Repositories包含在同一个包中 @EnableAutoConfiguration类的（或子包）。

检查存储库类是否在同一个包或子包中。如果不是，请更改@ComponentScan注释以提供存储库类所在的包。

org.springframework.beans.factory.UnsatisfiedDependencyException：通过索引为0的构造函数参数表示的不满意的依赖项

1 个答案: