Spring Boot无法找到Repository Bean问题求助

错误信息 #

Parameter 0 of constructor in dev.iosenberg.todo.controllers.TodoController required a bean of type 'dev.iosenberg.todo.repositories.TodoRepository' that could not be found.

相关代码 #

TodoApplication.java #

package dev.iosenberg.todo;

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

@SpringBootApplication
public class TodoApplication {

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

}

models/Todo.java #

package dev.iosenberg.todo.models;

import org.springframework.data.annotation.Id;

public record Todo(@Id Long id, Long userId, String name, String description, boolean completed) {

}

repositories/TodoRepository.java #

package dev.iosenberg.todo.repositories;

import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.stereotype.Repository;

import dev.iosenberg.todo.models.Todo;

@Repository
public interface TodoRepository extends CrudRepository<Todo,Long>, PagingAndSortingRepository<Todo, Long>{

}

controllers/TodoController.java #

package dev.iosenberg.todo.controllers;

import java.net.URI;
import java.util.Optional;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.data.web.SpringDataWebProperties.Pageable;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.util.UriComponentsBuilder;

import dev.iosenberg.todo.models.Todo;
import dev.iosenberg.todo.repositories.TodoRepository;

import java.util.List;

@RestController
@RequestMapping("/todos")
public class TodoController {
    @Autowired
    private TodoRepository todoRepository;
    
    public TodoController(TodoRepository todoRepository) {
        this.todoRepository = todoRepository;
    }

    @GetMapping
    public ResponseEntity<List<Todo>> findAll(Pageable pageable) {
        Page<Todo> page = todoRepository.findAll(
            PageRequest.of(1,1)
            );
        return ResponseEntity.ok(page.getContent());
    }

    @GetMapping("/{requestedId}")
    public ResponseEntity<Todo> findById(@PathVariable Long requestedId) {
        Optional<Todo> todoOptional = todoRepository.findById(requestedId);
        if(todoOptional.isPresent()) {
            return ResponseEntity.ok(todoOptional.get());
        }
        else {
            return ResponseEntity.notFound().build();
        }
    }

    @PostMapping
    public ResponseEntity<Void> createTodo(@RequestBody Todo newTodoRequest, UriComponentsBuilder ucb) {
        Todo savedTodo = todoRepository.save(newTodoRequest);
        URI locationOfNewTodo = ucb
            .path("todos/{id}")
            .buildAndExpand(savedTodo.id())
            .toUri();
        return ResponseEntity.created(locationOfNewTodo).build();
    }

    @PutMapping("/{id}")
    private ResponseEntity<Void> putTodo(@PathVariable Long id, @RequestBody Todo todoUpdate) {
        Optional<Todo> todoOptional = todoRepository.findById(id);
        if(todoOptional.isPresent()) {
            Todo updatedTodo = todoUpdate;
            todoRepository.save(updatedTodo);
            return ResponseEntity.noContent().build();
        }
        return ResponseEntity.notFound().build();
    }

    @DeleteMapping("/{id}")
    private ResponseEntity<Void> deleteTodo(@PathVariable Long id) {
        if(!todoRepository.existsById(id)) {
            return ResponseEntity.notFound().build();
        }
        todoRepository.deleteById(id);
        return ResponseEntity.noContent().build();
    }
}

MvcConfig.java #

package dev.iosenberg.todo;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MvcConfig implements WebMvcConfigurer {
    
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/home").setViewName("home");
        registry.addViewController("/").setViewName("home");
        registry.addViewController("/test").setViewName("test");
        registry.addViewController("/hello").setViewName("hello");
        registry.addViewController("/login").setViewName("login");
    }
}

build.gradle #

plugins {
    id 'java'
    id 'org.springframework.boot' version '3.1.5'
    id 'io.spring.dependency-management' version '1.1.3'
}

group = 'dev.iosenberg'
version = '0.0.1-SNAPSHOT'

java {
    sourceCompatibility = '17'
}

repositories {
    mavenCentral()
}

dependencies {
    // implementation 'org.springframework.boot:spring-boot-starter-security'
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    // implementation 'org.thymeleaf.extras:thymeleaf-extras-springsecurity6'
    implementation 'org.springframework.data:spring-data-jdbc'

    testImplementation 'com.h2database:h2'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    // testImplementation 'org.springframework.security:spring-security-test'
}

tasks.named('test') {
    useJUnitPlatform()
}

test {
    testLogging {
        events "passed", "skipped", "failed", "standardOut", "standardError"

        showExceptions true
        exceptionFormat "full"
        showCauses true
        showStackTraces true

        // Change to `true` for more verbose test output
        showStandardStreams = true
    }
}

控制台完整输出 #

2023-11-09T12:09:23.449-05:00  INFO 27748 --- [           main] dev.iosenberg.todo.TodoApplication       : Starting TodoApplication using Java 17.0.9 with PID 27748 (C:\Users\ikeos\Documents\git\todo\bin\main started by ikeos in C:\Users\ikeos\Documents\git\todo)
2023-11-09T12:09:23.455-05:00  INFO 27748 --- [           main] dev.iosenberg.todo.TodoApplication       : No active profile set, falling back to 1 default profile: "default"
2023-11-09T12:09:25.106-05:00  INFO 27748 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-11-09T12:09:25.119-05:00  INFO 27748 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-11-09T12:09:25.120-05:00  INFO 27748 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.15]     
2023-11-09T12:09:25.274-05:00  INFO 27748 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-11-09T12:09:25.277-05:00  INFO 27748 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1740 ms
2023-11-09T12:09:25.366-05:00  WARN 27748 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'todoController' defined in file [C:\Users\ikeos\Documents\git\todo\bin\main\dev\iosenberg\todo\controllers\TodoController.class]: Unsatisfied dependency expressed through constructor parameter 0: No qualifying bean of type 'dev.iosenberg.todo.repositories.TodoRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
2023-11-09T12:09:25.372-05:00  INFO 27748 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2023-11-09T12:09:25.395-05:00  INFO 27748 --- [           main] .s.b.a.l.ConditionEvaluationReportLogger : 

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2023-11-09T12:09:25.431-05:00 ERROR 27748 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Parameter 0 of constructor in dev.iosenberg.todo.controllers.TodoController required a bean of type 'dev.iosenberg.todo.repositories.TodoRepository' that could not be found.


Action:

Consider defining a bean of type 'dev.iosenberg.todo.repositories.TodoRepository' in your configuration. 

已尝试的解决方案 #

• 添加@ComponentScan指定基础包：消除了Repository Bean错误，但访问页面出现Whitelabel 404错误；
• 将测试资源下的data.sql和schema.sql移到src/main/resources：出现表不存在的SQL错误。

解决方案 #

1. 配置主环境数据源（以H2为例） #

Spring Data JDBC需要数据源才能创建Repository代理Bean，测试环境自动配置了H2，但主环境没有。在build.gradle中添加H2的运行时依赖：

runtimeOnly 'com.h2database:h2'

然后在src/main/resources下创建application.properties，添加H2配置：

spring.datasource.url=jdbc:h2:mem:tododb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.h2.console.enabled=true
spring.sql.init.mode=always

spring.sql.init.mode=always会自动执行src/main/resources下的schema.sql和data.sql初始化数据库。

2. 修正Controller注入方式 #

同时使用字段注入和构造注入会造成混淆，保留构造注入（Spring 4.3+无需@Autowired）：

@RestController
@RequestMapping("/todos")
public class TodoController {
    private final TodoRepository todoRepository;
    
    public TodoController(TodoRepository todoRepository) {
        this.todoRepository = todoRepository;
    }

    // 其他方法保持不变
}

3. 移除多余的@ComponentScan #

@SpringBootApplication已经包含@ComponentScan，默认扫描主类所在包（dev.iosenberg.todo）及所有子包，额外添加会导致扫描范围异常，引发404问题。

4. 确保数据库初始化文件存在 #

在src/main/resources下添加：
schema.sql

CREATE TABLE IF NOT EXISTS todo (
    id BIGINT AUTO_INCREMENT PRIMARY KEY,
    user_id BIGINT,
    name VARCHAR(255) NOT NULL,
    description TEXT,
    completed BOOLEAN DEFAULT FALSE
);

data.sql

INSERT INTO todo (user_id, name, description, completed) VALUES
(1, 'Learn Spring Data JDBC', 'Master basics of Spring Data JDBC', false),
(1, 'Build Todo App', 'Complete the todo application', false);

5. 验证页面访问 #

确保src/main/resources/templates下存在对应的Thymeleaf模板文件（如home.html），否则访问/home会出现404。示例home.html：

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>Home</title>
</head>
<body>
    <h1>Todo App Home</h1>
    <a href="/todos">View Todos API</a>
</body>
</html>

内容的提问来源于stack exchange，提问作者Ike Osenberg