Run Commands
Not all database commands have a specific helper method. However, you can
run any MongoDB command by using the MongoDatabase.runCommand()
method.
To learn more about MongoDB commands, see Database Commands in the Server manual.
Prerequisites
You must set up the following components to run the code examples in this guide:
A
test.restaurantscollection populated with documents from therestaurants.jsonfile in the documentation assets GitHub.The following import statements:
import com.mongodb.reactivestreams.client.MongoClients; import com.mongodb.reactivestreams.client.MongoClient; import com.mongodb.reactivestreams.client.MongoDatabase; import org.bson.Document;
Important
This guide uses the Subscriber implementations, which are
described in the Quick Start Primer.
Connect to a MongoDB Deployment
First, connect to a MongoDB deployment, then declare and define
a MongoDatabase instance.
The following code connects to a standalone
MongoDB deployment running on localhost on port 27017. Then, it
defines the database variable to refer to the test database:
MongoClient mongoClient = MongoClients.create(); MongoDatabase database = mongoClient.getDatabase("test");
To learn more about connecting to MongoDB deployments, see the Connect to MongoDB tutorial.
Run the buildInfo Command
To run the buildInfo command, construct a Document object that
specifies the command and pass it as a paramter to the runCommand() method.
The following sample code runs the buildInfo command and prints
the results:
database.runCommand(new Document("buildInfo", 1)).subscribe(new PrintDocumentSubscriber());