Get Last Inserted Document ID in MongoDB With Java Driver

Get Last Inserted Document ID in MongoDB With Java Driver

MongoDB is one of the most popular NoSQL databases available today. It provides powerful features and performance for developers who need to store and access data quickly and reliably. One of the common tasks for those using MongoDB is to get the last inserted document ID from a collection.

Fortunately, if you're using the Java driver for MongoDB, there is a straightforward way to do this. The Java driver provides a method called "getLastError()" which can be used to retrieve the last inserted document's ID. This method returns a DBObject containing the _id field and its associated value.

Here's a simple example of how to use the getLastError() method to get the last inserted document's ID:

MongoClient mongoClient = new MongoClient();

DB db = mongoClient.getDB("test");
DBCollection collection = db.getCollection("testCollection");

BasicDBObject document = new BasicDBObject();
document.put("name", "John Doe");

collection.insert(document);

DBObject lastDocID = collection.getLastError().get("_id");
System.out.println("Last Inserted Document ID: " + lastDocID);

This code will connect to a MongoDB server, create a collection, insert a document and then retrieve the last inserted document's ID. As you can see, it's very easy to do using the Java driver.

It's important to note that the getLastError() method only works when the write operation succeeds (which is the case in the example above). If the write operation fails, then the getLastError() method will return null.

This is a useful technique for any developers working with MongoDB and the Java driver. It allows you to quickly and easily retrieve the last inserted document's ID and use it for whatever purpose you need.