Thursday, June 7, 2012

Java MongoDB Tutorial

Working with MongoDB with java involves few steps
Step 1: include the java driver into the CLASSPATH
Step 2: start the mongodb service if installed
here is the demo code

package com.test;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

public class MongoHelloJava {

 public static void main(String[] args) {
  try {
   //Demonstrate simple hello java program with mongoDB
   System.out.println("Demonstarting simple insert and retrivel in MongoDB");
   // connect to mongoDB on default port and IP address
   Mongo mongo = new Mongo("localhost",27017);
   // getDB() return the database from MongoDB,
      //  mongoDB will create database automatically if not existed
   DB db = mongo.getDB("myMongoDB");
   // getCollection() returns the collection from MongoDB
   // mongoDB will create collection automatically if not existed
   DBCollection collection = db.getCollection("myCollection");
   // create a document to store key and value
   BasicDBObject document = new BasicDBObject();
   document.put("id", 1000);
   document.put("print", "hello  Java");
   // save it into collection named "myCollection"
   // query for searching perticular id
   BasicDBObject query = new BasicDBObject();
   query.put("id", 1000);
   // fire query
   DBCursor cursor = collection.find(query);
   // iterate through cursor
   // Demonstrate getCollection() and getCollections()
   System.out.println("Demonstrate getCollection() and getCollections()");
   Set<String> collections = db.getCollectionNames();

   for (String collectionName : collections) {

   //get a particular collection
     DBCollection collection1 = db.getCollection("myCollection");
   System.out.println("Collection Name is : "+collection1.toString());
   //insert the data into the database
   BasicDBObject document1 = new BasicDBObject();
   document1.put("post", "");
   document1.put("author", "Rajkumar Singh");
   BasicDBObject comments = new BasicDBObject();
   comments.put("user1", "text1");
   comments.put("user2", "text2");
   comments.put("user3", "text3");

   document.put("comment", comments);
   System.out.println("document1 inserted succesfully");
   //insertion of the data into the database through map
   Map<String, Object> documentMap = new HashMap<String, Object>();
   documentMap.put("post", "");
   documentMap.put("author", "Rajkumar Singh");
   Map<String, Object> commentMap = new HashMap<String, Object>();

   commentMap.put("user1", "text1");
   commentMap.put("user2", "text2");
   commentMap.put("user3", "text3");
   documentMap.put("comment", commentMap);
   collection.insert(new BasicDBObject(documentMap));
   DBCursor cursor1 = collection.find();
   while (cursor1.hasNext()) {
  } catch (UnknownHostException e) {
  } catch (MongoException e) {




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