由于未定义 MongoOperations bean，应用程序将无法启动
[英]Application won't start as MongoOperations bean is not defined
问题描述
I'm working through the book Learning Spring Boot 2.0, Second Edition but using Spring Boot 2.5.6 so I suspect my issue might be related to me having to do things slightly with the different version.
我正在阅读《 Learning Spring Boot 2.0, Second Edition 》一书，但使用Spring Boot 2.5.6 ，所以我怀疑我的问题可能与我不得不对不同的版本稍微做一些事情有关。
I have this class:我有这个 class：
@Component
public class InitDatabase {
@Bean
CommandLineRunner init(MongoOperations operations) {
return args -> {
operations.dropCollection(Image.class);
operations.insert(new Image("1", "learning-spring-boot-cover.jpg"));
operations.insert(new Image("2", "learning-spring-boot-2nd-edition-cover.jpg"));
operations.insert(new Image("3", "bazinga.png"));
operations.findAll(Image.class).forEach(image -> System.out.println(image.toString()));
};
}
}
When I run my application I get this error:当我运行我的应用程序时，我收到此错误：
2021-11-25 12:26:42.870 DEBUG 71010 --- [ main] osbdLoggingFailureAnalysisReporter: Application failed to start due to an exception
org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.data.mongodb.core.MongoOperations' available: expected at least 1 bean which qualifies as autowire candidate.
2021-11-25 12:26:42.870 ERROR 71010 --- [ main] osbdLoggingFailureAnalysisReporter:
APPLICATION FAILED TO START
Description:
Parameter 0 of method init in com.paulcarron.learningspringboot.learningspringboot.InitDatabase required a bean of type 'org.springframework.data.mongodb.core.MongoOperations' that could not be found.
Action:
Consider defining a bean of type 'org.springframework.data.mongodb.core.MongoOperations' in your configuration.
This is my build.gradle :这是我的build.gradle ：
plugins {
id 'org.springframework.boot' version '2.5.6'
id 'io.spring.dependency-management' version '1.0.11.RELEASE'
id 'java'
}
group = 'com.paulcarron.learningspringboot'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'
configurations {
compileOnly {
extendsFrom annotationProcessor
}
}
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-data-mongodb-reactive'
implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
implementation 'org.springframework.boot:spring-boot-starter-webflux'
implementation 'org.synchronoss.cloud:nio-multipart-parser:1.1.0'
compileOnly 'org.projectlombok:lombok'
annotationProcessor 'org.projectlombok:lombok'
testImplementation 'de.flapdoodle.embed:de.flapdoodle.embed.mongo'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
testImplementation 'io.projectreactor:reactor-test'
implementation 'org.springframework.boot:spring-boot-starter-actuator'
implementation 'javax.persistence:javax.persistence-api:2.2'
}
test {
useJUnitPlatform()
}
My understanding is that I don't need to activate the with @EnableReactiveMongoRepositories as this is done automatically if Reactive MongoDB or Spring DataMongoDB 2.0+ are on the classpath.我的理解是，我不需要使用@EnableReactiveMongoRepositories激活，因为如果 Reactive MongoDB 或 Spring DataMongoDB 2.0+ 在类路径上，这是自动完成的。
Is there any obvious reason why this is not working?这不起作用有什么明显的原因吗？
3 个解决方案
解决方案1
1 2021-11-25 15:23:27
I guess you're trying to init your database on the startup.我猜你正试图在启动时初始化你的数据库。
You can leverage the spring internal event mechanism.您可以利用 spring 内部事件机制。 When your application is ready, spring triggers the event ApplicationReadyEvent当您的应用程序准备就绪时，spring 会触发事件ApplicationReadyEvent
You can listen to this event and init your collection:您可以收听此事件并初始化您的收藏：
@Component
public class DataInit implements ApplicationListener<ApplicationReadyEvent> {
private final MongoOperations operations;
public DataInit(MongoOperations operations) {
this.operations = operations;
}
@Override
public void onApplicationEvent(ApplicationReadyEvent event) {
// init data
}
}
If you want to know more about spring events --> https://www.baeldung.com/spring-events如果您想了解更多关于 spring 事件的信息 --> https://www.baeldung.com/spring-events
解决方案2
1 2021-11-25 16:15:37
MongoOperations is the interface for interacting with Mongo in a blocking manner. MongoOperations是以阻塞方式与 Mongo 交互的接口。 ReactiveMongoOperations is the interface for interacting with Mongo in a reactive manner. ReactiveMongoOperations是用于以响应方式与 Mongo 交互的接口。
As you're using WebFlux ( spring-boot-starter-webflux ), it would appear that you want to build a reactive application.当您使用 WebFlux ( spring-boot-starter-webflux ) 时，您似乎想要构建一个反应式应用程序。 If so, you should replace your use of MongoOperations with ReactiveMongoOperations .如果是这样，你应该用ReactiveMongoOperations替换你对MongoOperations的使用。 The, if you want to build a blocking, Servlet-based web application would be to switch to spring-boot-starter-data-mongodb and spring-boot-starter-web .如果您想构建一个阻塞的、基于 Servlet 的 web 应用程序，则需要切换到spring-boot-starter-data-mongodb和spring-boot-starter-web 。
解决方案3
0 2021-11-25 16:26:25
I want to preload data and read that it was best to do this using a blocking API because when launching an application there is a risk of a thread lock issue when both the web container and my loader are starting up.我想预加载数据并读到最好使用阻塞的 API 来执行此操作，因为在启动应用程序时，当 web 容器和我的加载器正在启动时，存在线程锁定问题的风险。 The book I'm using is for an older veriosn of both Spring Boot and MongoDB.我正在使用的这本书适用于 Spring Boot 和 MongoDB 的旧版本。
It seems that the version of spring-boot-starter-data-mongodb-reactive that the book used contained MongoOperations but this was then split out.似乎本书使用的spring-boot-starter-data-mongodb-reactive版本包含MongoOperations但随后被拆分。 See this .看到这个。
To use this I added implementation 'org.springframework.boot:spring-boot-starter-data-mongodb' to my class path.为了使用它，我将implementation 'org.springframework.boot:spring-boot-starter-data-mongodb'添加到我的 class 路径中。
If there wasn't the issue of thread lock I could have used ReactiveMongoOperations instead.如果没有线程锁的问题，我可以使用ReactiveMongoOperations代替。
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