Archives: MongoDB

Java MongoDB – Get Collection from Database

[code lang=”java”]import java.net.UnknownHostException;
import java.util.Set;

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

public class GetCollectionApp {

public static void main(String[] args) {
try {
Mongo mongo = new Mongo("localhost", 27017);
DB db = mongo.getDB("yourdb");

// get entire list of collections
Set<String> collections = db.getCollectionNames();

for (String collectionName : collections) {
System.out.println(collectionName);
}

// get a single collection
DBCollection collection = db.getCollection("yourCollection");
System.out.println(collection.toString());

System.out.println("Done");

} catch (UnknownHostException e) {
e.printStackTrace();
} catch (MongoException e) {
e.printStackTrace();
}
}

}[/code]


Java – Convert JSON to MongoDB Object

JSON Data to Convert:

{
‘name’ : ‘javac’,
‘age’ : 6
}

Conversion Code:
[code lang=”java”]import java.net.UnknownHostException;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.Mongo;
import com.mongodb.MongoException;
import com.mongodb.util.JSON;

public class App {

public static void main(String[] args) {
try {

Mongo mongo = new Mongo("localhost", 27017);
DB db = mongo.getDB("yourdb");
DBCollection collection = db.getCollection("dummyColl");

// convert JSON to DBObject directly
DBObject dbObject = (DBObject) JSON.parse("{‘name’:’javac’, ‘age’:6}");

collection.insert(dbObject);

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

System.out.println("Done");

} catch (UnknownHostException e) {
e.printStackTrace();
} catch (MongoException e) {
e.printStackTrace();
}
}

}[/code]

Output:

{ “_id” : { “$oid” : “4dc9ebb5237f275c2fe4959f”} , “name” : “javac” , “age” : 6}
Done