Spring无法扫描MongoRepository

Question

我有一个实现MongoRepository接口的持久接口，如下所示：

package org.prithvidiamond1.DB.Repositories;

import org.prithvidiamond1.DB.Models.SomeModel;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface ServerRepository extends MongoRepository<SomeModel, String> {
}

尽管如此，我仍然得到以下错误：

Exception encountered during context initialization - cancelling refresh attempt:
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'botApplication': 
Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: 
No qualifying bean of type 'org.prithvidiamond1.DB.Repositories.ServerRepository' available: expected at least 1 bean which qualifies as autowire candidate.
Dependency annotations: {}


PPLICATION FAILED TO START
***************************

Description:

Parameter 0 of constructor in org.prithvidiamond1.BotApplication required a bean of type 'org.prithvidiamond1.DB.Repositories.ServerRepository' that could not be found.


Action:

Consider defining a bean of type 'org.prithvidiamond1.DB.Repositories.ServerRepository' in your configuration.

我尝试过许多解决方案(自定义@ComponentScan、使用@Service而不是@Component等)。我在网上发现，但没有人能帮我解决这个问题，有人能不能向我解释一下是怎么回事，我该如何解决这个问题？

注意:目录结构如下(这不是完整的目录结构，但我认为这应该足够了解)：

org.prithvidiamond1
   |
   +--BotApplication.java
   |
   +--DB
      |
      +--Repository
      |
      +--ServerRepository.java

BotApplication.java看起来如下：

package org.prithvidiamond1;

import org.jc.api.Api;
import org.jc.api.ApiBuilder;
import org.jc.api.entity.server.Server;
import org.prithvidiamond1.DB.Models.Server;
import org.prithvidiamond1.DB.Repositories.ServerRepository;
import org.slf4j.Logger;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;

import java.util.Collection;

@Component
public class BotApplication {
    private final Api api;
    private final ServerRepository serverRepository;

    public BotApplication(ServerRepository serverRepository, Logger logger){
        String botToken = System.getenv().get("BOT_TOKEN");

        this.api = new ApiBuilder();

        this.serverRepository = serverRepository;

        appRuntime(logger);
    }

    public void appRuntime(Logger logger){
        logger.info("Bot has started!");

        // Handling server entries in the database
        if (this.serverRepository.findAll().isEmpty()) {
            logger.trace("server data repository empty, initializing data repository...");
            Collection<Server> servers = api.getServers();
            for (Server server : servers) {
                this.serverRepository.save(new Server(String.valueOf(server.getId())));
            }
            logger.trace("server data repository initialized");
        }
    }

    @Bean
    public Api getApi() {
        return this.api;
    }
}

编辑:下面是一个包含所有代码的存储库的链接：https://github.com/prithvidiamond1/DiamondBot/tree/springboot-restructure

Answer 1

问题在于您正在使用主源类(BotApplication.class)在启动过程中执行自定义代码。

    public static void main(String[] args) {
        ApplicationContext AppContext = SpringApplication.run(BotApplication.class, args);
    }

    public BotApplication(DiscordServerRepository serverRepository, Logger logger){
        ...
        appRuntime(logger);
    }

它不是一个使用存储库或任何启动代码的好地方。

在SpringApplication.run方法中，只需要传递提供bean定义的类。这些是@配置类。

参见最佳实践在Spring启动后运行代码

我描述了最好的解决方案之一： ApplicationRunner

1. BotApplication类必须实现ApplicationRunner接口。该接口用于指示当bean包含在SpringApplication中时，它应该运行。 在run方法中执行所有启动代码。

@Component
public class BotApplication implements ApplicationRunner {
    private final DiscordApi api;
    private final DiscordServerRepository serverRepository;

    private final Logger logger;

    public BotApplication(DiscordServerRepository serverRepository, Logger logger){
        String botToken = System.getenv().get("BOT_TOKEN");
        this.logger = logger;
        this.serverRepository = serverRepository;
        this.api = new DiscordApiBuilder()
                .setToken(botToken)
                .setAllIntents()
                .setWaitForServersOnStartup(true)
                .setWaitForUsersOnStartup(true)
                .login().exceptionally(exception -> {    // Error message for any failed actions from the above
                    logger.error("Error setting up DiscordApi instance!");
                    logger.error(exception.getMessage());
                    return null;
                })
                .join();
    }

    public void appRuntime(Logger logger){
        logger.info("Bot has started!");

        // Handling server entries in the database
        if (this.serverRepository.findAll().isEmpty()) {
            logger.trace("Bot server data repository empty, initializing data repository...");
            Collection<Server> servers = api.getServers();
            for (Server server : servers) {
                this.serverRepository.save(new DiscordServer(String.valueOf(server.getId()), Main.defaultGuildPrefix));
            }
            logger.trace("Bot server data repository initialized");
        }
    }

    @Bean
    public DiscordApi getApi() {
        return this.api;
    }

    @Override
    public void run(ApplicationArguments args) throws Exception {
        appRuntime(logger);
    }
}

1. 将Main.class传递给SpringApplication.run

@SpringBootApplication
@EnableMongoRepositories
public class Main {
    public static void main(String[] args) {
        ApplicationContext AppContext = SpringApplication.run(Main.class, args);
    }
}

Answer 2

在类的构造函数中使用注解@Autowired，如下所示-

@Autowired
public BotApplication(ServerRepository serverRepository, Logger logger){
        String botToken = System.getenv().get("BOT_TOKEN");

        this.api = new ApiBuilder();

        this.serverRepository = serverRepository;

        appRuntime(logger);
    }

Answer 3

您需要在主应用程序类之上使用@EnableMongoRepositories来启用对mongo存储库bean的扫描。