如何在gradle Springboot REST应用程序中将heroku连接到mongodb？

Question

I followed this guide to set up a gradle Springboot service with mongoDB, then followed the deployment instructions for heroku. I also added the mongoLab addOn. It works perfectly on localhost, but when database parts are reached on heroku, the responses stall indefinitely. When I remove the mongoDB lines and re-deploy, the responses work perfectly. How can I deploy this app to heroku with mongoDB working?

EDIT: this is the error from heroku logs

org.mongodb.driver.cluster : No server chosen by WritableServerSelector from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, serverDescriptions=[ServerDescription{address=localhost:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.ConnectException: Connection refused (Connection refused)}}]}. Waiting for 30000 ms before timing out

Answer 1

I had to add a mongoLab configuration.

@Configuration
public class MongoLabConfiguration {

  public @Bean MongoDbFactory mongoDbFactory() throws MongoException, UnknownHostException {
    return new SimpleMongoDbFactory(new MongoClientURI(System.getenv("MONGODB_URI")));
  }
  public @Bean
    MongoTemplate mongoTemplate() throws Exception {
        return new MongoTemplate(mongoDbFactory());
  }
}