MongoDB - Java - Retrieving Documents

MongoDB provides MongoCollection class to find or retrieve document(s) from a collection.

Syntax

// Select a collection
MongoCollection<Document> collection =  database.getCollection("sampleCollection");

// Getting the iterable object
FindIterable<Document> iterDoc = collection.find();
int i = 1;
// Getting the iterator
Iterator<Document> it = iterDoc.iterator();
while (it.hasNext()) {
   System.out.println(it.next());
   i++;
}        	      

Inserting a Document in a Collection

To insert a document, we first need to connect to a database and then select the collection and then insert the document as shown below −

package com.tutorialspoint.mongodb;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.bson.Document;

import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;  
public class MongoDBTester { 

   public static void main( String args[] ) { 

      String uri = "mongodb://localhost:27017/";

      try (MongoClient mongoClient = MongoClients.create(uri)) {
         MongoDatabase database = mongoClient.getDatabase("myDb");

         //select a collection
         MongoCollection<Document> collection =  database.getCollection("sampleCollection"); 

         Document document = new Document("title", "RethinkDB")
            .append("description", "database")
            .append("likes", 200)
            .append("url", "http://www.tutorialspoint.com/rethinkdb/")
            .append("by", "tutorials point");
         List<Document> list = new ArrayList<Document>();
         list.add(document);

         collection.insertMany(list);
         // Getting the iterable object
         FindIterable<Document> iterDoc = collection.find();
         int i = 1;
         // Getting the iterator
         Iterator<Document> it = iterDoc.iterator();
         while (it.hasNext()) {
            System.out.println(it.next());
            i++;
         }        	      
      }
   } 
}

Output

Now, let's compile and run the above program to select a document from a collection in our database myDb.

On executing, the above program gives you the following output.

Document{{_id=69673eabfe1a70a594cd116b, title=MongoDB, description=database, likes=100, url=http://www.tutorialspoint.com/mongodb/, by=tutorials point}}
Document{{_id=69675615b8a497382adfd88e, title=RethinkDB, description=database, likes=200, url=http://www.tutorialspoint.com/rethinkdb/, by=tutorials point}}