how to get record from MongoDB

[malik ge]

Hi,
I am a new-bee to mongodb and first time using it with Java.

I am creating a simple logIn page.
The following code run fine, and get all the record matching the "firstName" and "password".

BasicDBObject searchQuery = new BasicDBObject();
searchQuery.put("firstName", firstName);
searchQuery.put("password", pass);

DBCursor cursor = collection.find(searchQuery);
            
while(cursor.hasNext())
{
   System.out.println(cursor.next());
}

While using Java with MySql, by doing:

String fname = resultset.getString("firstName");
String pass= resultset.getString("password");
String lastName = resultset.getString("lastName");

I can get the values from MySql database and stores it in some variables.
With mongoDB how I get each value separately from a document and store it in variable?
Thanks

[chris webster]

Remember a query in MongoDB returns one or more documents in BSON format (like JSON). I'm new to MongoDB as well, but I think the individual documents are instances of BasicDBObject, which inherits from BasicBSONObject - this has various "get" methods to get individual elements by their key etc.

Check out the MongoDB Java API documentation.

[Mohamed Sanaulla]

When you do a DBCursor.next() you can get hold of the DBObject instance. Something like:

DBObject dbObject = cursor.next();
Object firstName = dbObject.get("firstName);
Object password = dbObject.get("password");

you then have to correspondingly cast to the required type. I am not sure if you can cast the return of cursor.next() directly into BasicDBObject and then make use of getInt, getBoolean, getString method provided by BasicDBObject. Something like:

BasicDBObject dbObject = (BasicDBObject)cursor.next();
String firstName = dbObject.getString("firstName");
String password = dbObject.getString("password");

If you are familiar with ORM frameworks then you can try out Morphia which helps in making these operations a bit simpler.

As Chris pointed out, the MongoDB Java documentation should help you a lot.

[malik ge]

By doing this, I am able to get the records from the mongodb.

BasicDBObject searchQuery = new BasicDBObject();  
searchQuery.put("firstName", firstName);  
searchQuery.put("password", pass);  
  
DBCursor cursor = collection.find(searchQuery);  
              
while(cursor.hasNext())  
{  
   System.out.println(cursor.next()); 
   String firstName = searchQuery.getString("firstName");  
   String lastName = searchQuery.getString("lastName");
}

But how can I get the "_id" object from the database.

This shows the all the record:
System.out.println(cursor.next());

{ "_id" : { "$oid" : "4fc68190a09ef7490a0b3b40"} , "firstName" : "Some First Name" , "lastName" : "Some Last Name"}

But when I try to get the id, it gives me "null" value

[Mohamed Sanaulla]

You need to have a look at ObjectId class from the MongoDB documentation.

Recently I wrote an article which on a blog- Using Morphia- Java Library for MongoDB. Here I compared using MongoDB driver and Morphia API.

PS: I was reluctant to share this link in my first reply tending it to be Blatant Advertisement. But I have code samples there which show you how to retrieve the "id" field from Mongo's BSON

[malik ge]

Mohamed Sanaulla wrote:You need to have a look at ObjectId class from the MongoDB documentation.

Recently I wrote an article which on a blog- Using Morphia- Java Library for MongoDB. Here I compared using MongoDB driver and Morphia API.

PS: I was reluctant to share this link in my first reply tending it to be Blatant Advertisement. But I have code samples there which show you how to retrieve the "id" field from Mongo's BSON

Thanks a lot man.
That is exactly what I am looking for.
It has not only clarify my current problem, but also helped me understanding some other useful things.
Thanks again.

[Mohamed Sanaulla]

Glad that it was useful!

[Johnc Smith]

Hello
I know it’s too late, I think your query will be solved now. I would like to share a website, where discussions are carry on related to MongoDB and many other. Here is the link: https://zappysys.com/blog/ssis-loading-data-into-mongodb-upsert-update-delete-insert/.