Spring Boot新增Repository后无法找到GameRepository Bean的问题

相关代码 #

GameRepository.java #

@Repository
public interface GameRepository extends MongoRepository<Game, String> {
}

GameRepositoryReactive.java #

@Repository
public interface GameRepositoryReactive extends ReactiveMongoRepository<Game, String> {
}

Game.java #

@Data
@AllArgsConstructor
@NoArgsConstructor
@Document(collection = "games")
public class Game{
    @Id
    String id;
    String name;
}

GameService.java #

private final GameRepositoryReactive gameRepositoryReactive;
private final GameRepository gameRepository;

public GameService(GameRepository gameRepository, GameRepositoryReactive gameRepositoryReactive) {
    this.gameRepositoryReactive = gameRepositoryReactive;
    this.gameRepository = gameRepository;
}

错误信息 #

com.example.service.GameService构造函数的第0个参数需要类型为'com.example.repository.GameRepository'的bean，但未找到。

问题背景 #

仅使用ReactiveMongoRepository时无此错误，同时引入阻塞式MongoRepository和响应式ReactiveMongoRepository时触发该问题。

原因分析 #

Spring Boot在同时引入阻塞式MongoDB依赖（spring-boot-starter-data-mongodb）和响应式MongoDB依赖（spring-boot-starter-data-mongodb-reactive）时，默认优先配置响应式Mongo相关Bean，不会自动创建阻塞式的MongoTemplate及对应Repository支持，导致MongoRepository接口无法被实例化为Bean。

解决方案 #

方案1：显式配置阻塞式MongoRepository支持 #

创建配置类，手动开启阻塞式MongoRepository扫描并配置MongoTemplate：

@Configuration
@EnableMongoRepositories(
    basePackages = "com.example.repository",
    repositoryFactoryBeanClass = MongoRepositoryFactoryBean.class
)
public class BlockingMongoConfig {
    @Bean
    public MongoTemplate mongoTemplate(MongoDatabaseFactory databaseFactory) {
        return new MongoTemplate(databaseFactory);
    }
}

若需确保响应式Repository正常生效，可单独配置响应式Repository扫描：

@Configuration
@EnableReactiveMongoRepositories(
    basePackages = "com.example.repository",
    repositoryFactoryBeanClass = ReactiveMongoRepositoryFactoryBean.class
)
public class ReactiveMongoConfig {
    @Bean
    public ReactiveMongoTemplate reactiveMongoTemplate(ReactiveMongoDatabaseFactory databaseFactory) {
        return new ReactiveMongoTemplate(databaseFactory);
    }
}

方案2：移除不必要的阻塞式Repository #

若业务无需阻塞式数据库操作，直接删除GameRepository接口，并修改GameService移除对应依赖：

private final GameRepositoryReactive gameRepositoryReactive;

public GameService(GameRepositoryReactive gameRepositoryReactive) {
    this.gameRepositoryReactive = gameRepositoryReactive;
}

内容的提问来源于stack exchange，提问作者Rony Tesler