用Java将MongoDB数组中的所有ID相加

import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;

MongoClient mongoClient = new MongoClient("localhost", 27017);
MongoDatabase database = mongoClient.getDatabase("your_database_name");
MongoCollection<Document> collection = database.getCollection("your_collection_name");

Document query = new Document();
Document projection = new Document("_id", 1);
List<Document> documents = collection.find(query).projection(projection).into(new ArrayList<>());

int sum = 0;
for (Document document : documents) {
    int id = document.getInteger("_id");
    sum += id;
}

System.out.println("Sum of IDs: " + sum);