How to Insert a HashMap Into MongoDB With Java?

How to Insert a HashMap Into MongoDB With Java?

Using MongoDB's Java driver, you can easily insert a HashMap object into your MongoDB database. In this tutorial, we will go through the steps of inserting a HashMap object into MongoDB with Java.

Step 1: Install the MongoDB Java Driver

The first step is to install the MongoDB Java driver. To install it, you can use either Maven or Gradle.

Install Using Maven

If you are using Maven, add the following dependency to your pom.xml file:

<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.6.3</version>
</dependency>

Install Using Gradle

If you are using Gradle, add the following dependency to your build.gradle file:

compile 'org.mongodb:mongo-java-driver:3.6.3'

Step 2: Create a MongoClient

Once the MongoDB Java driver is installed, the next step is to create an instance of MongoClient. This is the main entry point for connecting to a MongoDB database and performing read/write operations on the data. You can create an instance of MongoClient like this:

MongoClient mongoClient = new MongoClient("localhost", 27017);

The first argument is the hostname of the MongoDB server, and the second argument is the port number.

Step 3: Get a MongoDatabase Object

Once you have a MongoClient instance, you can get a reference to a MongoDB database like this:

MongoDatabase db = mongoClient.getDatabase("mydb");

This will create an instance of MongoDatabase for the database named "mydb" in MongoDB.

Step 4: Create a MongoCollection Instance

Once you have a MongoDatabase instance, you can create a MongoCollection instance like this:

MongoCollection<Document> collection = db.getCollection("mycol");

This will create a MongoCollection instance for the collection named "mycol" in the given MongoDB database.

Step 5: Insert the HashMap into MongoDB

Now that you have a MongoCollection instance, you can insert a HashMap object into MongoDB like this:

HashMap<String, Object> map = new HashMap<String, Object>();
map.put("key1", "value1");
map.put("key2", "value2");

// Create a Document from the HashMap
Document document = new Document(map);

// Insert the document into MongoDB
collection.insertOne(document);

This will insert a Document containing the HashMap into the MongoDB collection.

Conclusion

In this tutorial, we learned how to insert a HashMap object into MongoDB with Java. We started by installing the MongoDB Java driver, then we created a MongoClient, got a MongoDatabase object, and finally inserted the HashMap into the MongoDB collection.