How to sort the documents of a MongoDB collection using java?


While retrieving records from a MongoDB collection, you can sort the records in the result using the sort() method.

Syntax

db.COLLECTION_NAME.find().sort({KEY:1})

The Java MongoDB library provides a method with the same name, to limit the number of records invoke this method (on the result of the find() method) by passing the type of the sort (ascending or descending) and the field name based on which you want to sort the records as −

sort(Sorts.ascending("age");

Example

import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Sorts;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.bson.Document;
import com.mongodb.MongoClient;
public class SortingRecords {
   public static void main( String args[] ) {
      //Creating a MongoDB client
      MongoClient mongo = new MongoClient( "localhost" , 27017 );
      //Connecting to the database
      MongoDatabase database = mongo.getDatabase("myDatabase");
      //Creating a collection object
      MongoCollection<Document> collection = database.getCollection("students");
      Document document1 = new Document("name", "Ram").append("age", 26).append("city", "Hyderabad");
      Document document2 = new Document("name", "Robert").append("age", 27).append("city", "Vishakhapatnam");
      Document document3 = new Document("name", "Rhim").append("age", 30).append("city", "Delhi");
      Document document4 = new Document("name", "Radha").append("age", 28).append("city", "Mumbai");
      Document document5 = new Document("name", "Ramani").append("age", 45).append("city", "Pune");
      //Inserting the created documents
      List<Document> list = new ArrayList<Document>();
      list.add(document1);
      list.add(document2);
      list.add(document3);
      list.add(document4);
      list.add(document5);
      collection.insertMany(list);
      System.out.println("Documents Inserted");
      //Retrieving a collection object
      collection = database.getCollection("students");
      //Retrieving the documents with a limit
      FindIterable<Document> iterDoc =
      collection.find().sort(Sorts.ascending("age"));
      Iterator it = iterDoc.iterator();
      while (it.hasNext()) {
         System.out.println(it.next());
      }
   }
}

Output

Documents Inserted
Document{{_id=5e88843d5c851b345fce2a33, name=Ram, age=26, city=Hyderabad}}
Document{{_id=5e88843d5c851b345fce2a34, name=Robert, age=27, city=Vishakhapatnam}}
Document{{_id=5e88843d5c851b345fce2a36, name=Radha, age=28, city=Mumbai}}
Document{{_id=5e88843d5c851b345fce2a35, name=Rhim, age=30, city=Delhi}}
Document{{_id=5e88843d5c851b345fce2a37, name=Ramani, age=45, city=Pune}}

Updated on: 10-Apr-2020

1K+ Views

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