构造函数的参数 0 需要一个找不到的 bean

Question

I am not sure what is wrong with my codes. I was trying to learn Spring Boot WebFlux. But I am not able to run the application as i get the below error

" Parameter 0 of constructor in com.thomsoncodes.todo.controller.ToDoController required a bean of type 'com.thomsoncodes.todo.repository.ToDoRespository' that could not be found."

Tired @Autowired but still I have the same error.

Here is my code

build.gradle

plugins {
  id 'org.springframework.boot' version '2.1.3.RELEASE'
  id 'java'
}

apply plugin: 'io.spring.dependency-management'

group = 'com.thomsoncodes.todo'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

repositories {
  mavenCentral()
}

dependencies {
   implementation 'org.springframework.boot:spring-boot-starter-webflux'
   compileOnly 'org.projectlombok:lombok'
   testImplementation 'org.springframework.boot:spring-boot-starter-test'
   testImplementation 'io.projectreactor:reactor-test'
}

Application class

package com.thomsoncodes.todo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootTodoWebfluxApplication {

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

}

Controller class

package com.thomsoncodes.todo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import com.thomsoncodes.todo.domain.ToDo;
import com.thomsoncodes.todo.repository.ToDoRespository;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

@RestController
public class ToDoController {

   private ToDoRespository repository;

   public ToDoController(ToDoRespository repository) {
    this.repository = repository;
   }

   @GetMapping("/rodo/{id}")
   public Mono<ToDo> getTodo(@PathVariable String id) {
      return this.repository.findById(id);
   }

   @GetMapping("/todo")
   public Flux<ToDo> getToDos() {
      return this.repository.findAll();
   }
}

domain class

 package com.thomsoncodes.todo.domain;

 import java.time.LocalDateTime;
 import java.util.UUID;

 import lombok.Data;

 @Data
 public class ToDo {
 private String id;
 private String description;
 private LocalDateTime created;
 private LocalDateTime modified;
 private boolean completed;

 public ToDo() {
    this.id = UUID.randomUUID().toString();
    this.created = LocalDateTime.now();
    this.modified = LocalDateTime.now();
 }

 public ToDo(String description) {
    this();
    this.description = description;     
 }

 public ToDo(String description, boolean completed) {
    this();
    this.description = description;
    this.completed = completed;
  }
}

Repository class

package com.thomsoncodes.todo.repository;

import java.util.Arrays; 
import com.thomsoncodes.todo.domain.ToDo;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

public class ToDoRespository {

private Flux<ToDo> toDoFlux = Flux.fromIterable(Arrays.asList(
        new ToDo("Do Homework"),
        new ToDo("Workout in the morning", true),
        new ToDo("Make dinner tonight"),
        new ToDo("Clean the studio", true),
        new ToDo("Learn spring boot", true)));

  public Mono<ToDo> findById(String id) {
    return Mono.from(
            toDoFlux.filter( todo -> todo.getId().equals(id)));
  }

  public Flux<ToDo> findAll() {
     return toDoFlux;
  }


}

Answer 1

You need to make a couple of changes,

1. Annotate ToDoRepository with @Repository or @Component
2. Annotate ToDoRepository with @Autowired in controller class (optional)

Answer 2

ToDoRepository 未标记为@Component。

Answer 3

Hystrix

In CitcuitBreakClient, I put @Component but still i have issue of bean not found

 public class CircuitBreakerService {

 //@Service
 @Component
 public class BookService {

  private final RestTemplate restTemplate;

  public BookService(RestTemplate rest) {
    this.restTemplate = rest;
  }

  @HystrixCommand(fallbackMethod = "reliable")
  public String readingList() {
    URI uri = URI.create("http://localhost:8060/recommended");

    return this.restTemplate.getForObject(uri, String.class);
  }

  public String reliable() {
    return "Cloud not navigate to Circuit Breaker Server";
  }

}

@RestController
@CrossOrigin
@RequestMapping("/read")
public class CircuitBreakerController {

BookService bookService;

@Autowired
CircuitBreakerController(BookService bs){
    this.bookService=bs;
}

@RequestMapping("/get")
public String toRead() {
    return bookService.readingList();
  }

}

Answer 4

Yeah, found out adding @AutoConfiguration to the class where the issue is happening usually solves the problem for this bug.