BE THE CODER > No SQL > Mongo DB Examples > How to get distinct values for a given key

MongoDB is a scalable, high-performance, open source NoSQL database. It offers Ad hoc queries, Indexing, Replication, Load balancing, File storage (GridFS), Aggregation, MapReduce and Server-side JavaScript execution. This requires the library mongo-2.8.0.jar to be present in the classpath. The following example shows how to get distinct values of a field.

File Name :	com/bethecoder/tutorials/mongodb/tests/GetDistinctTest.java
Author :	Sudhakar KV
Email :	[email protected]


package com.bethecoder.tutorials.mongodb.tests;



import java.net.UnknownHostException;

import java.util.List;



import com.mongodb.DB;

import com.mongodb.DBCollection;

import com.mongodb.Mongo;

import com.mongodb.MongoException;



public class GetDistinctTest {



  /**

   * @param args

   */

  @SuppressWarnings("unchecked")

  public static void main(String[] args) {



    try {

      //Connect to mongoDB with given IP and PORT

      Mongo mongo = new Mongo("localhost", 27017);

      

      //Get the database object

      DB database = mongo.getDB("mytestdb");

      

      //Gets a collection with a given name.

      DBCollection countries = database.getCollection("mycountries");

      

      //Get distinct values for this key

      List countryNames = countries.distinct("country");

      System.out.println(countryNames);

      

      List stateNames = countries.distinct("state");

      System.out.println(stateNames);

      

    } catch (UnknownHostException e) {

      e.printStackTrace();

    } catch (MongoException e) {

      e.printStackTrace();

    }

  }

}