java - 有没有办法检查mongoDB连接的正确性？

Question

在我的 spring boot 应用程序中，我使用 spring-boot-starter-data-mongodb:2.1.3 来获取 MongoDB 的连接。我有一些属性文件来配置 mongoDB:

 spring.data.mongodb.host=localhost
 spring.data.mongodb.port=27017
 spring.data.mongodb.database=database

如果我设置了不正确的主机名(spring.data.mongodb.host=不正确的主机)或端口，我的应用程序将成功启动。但我希望该应用程序失败，就像我设置错误格式的主机名一样 (spring.data.mongodb.host=hxxt://wrongFormat)

Caused by: com.mongodb.MongoException: host and port should be specified in host:port format

我怎样才能做到这一点？

示例:

应用程序属性

 #Wrong host
 spring.data.mongodb.host=www.google.com
 spring.data.mongodb.port=27017
 spring.data.mongodb.database=database

DemoApplication.java:

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

配置.java:

@Configuration
public class Config {
    @Bean
    public CommandLineRunner commandLineRunner(JobRepository jobRepository ){
        return args -> jobRepository.findById("1");
    }
}  

JobRepository.java:

  public interface JobRepository extends MongoRepository<Job, String> {}

作业.java:

  @Getter
  @Setter
  @EqualsAndHashCode
  @NoArgsConstructor
  @Document(collection = "Jobs")
  public class Job {
     @Id
     private String id = null;
     private String field;
  }

Answer 1

您的问题是 mongo 上的连接检查是异步发生的。因此，如果输入正确，则 bean 均由 spring boot 创建，稍后连接会失败。您可以通过定义一个在启动时检查连接的 bean 来强制它爆炸。例如，我使用这个:

/**
 * This is a testing bean. It is only here to explode when the database is not available.
 * This is to counter act default spring boot behaviour where the Mongo configuration
 * will connect to a localhost DB regardless of whether it exists or not.  
 *
 */
public class MongoDatabaseVerifier {
    private static final Logger log = LoggerFactory.getLogger(MongoDatabaseVerifier.class);

    public MongoDatabaseVerifier(MongoClient mongoClient) {
        checkConnectionOrThrow(mongoClient);
    }

    /**
     * Calls {@link MongoClient#getAddress()} and throws the result away if successful 
     * @param client
     */
    void checkConnectionOrThrow(MongoClient client) { 
        client.getAddress(); // this will either succeed super fast or explode
        log.info("Database fully started ...");
    }
}

由于该 bean 在创建时进行检查，因此 spring 仅在成功时才会继续启动。否则，将抛出 Bean 创建异常并中止启动。

希望对您有帮助