remove _id from mongodb result java

5
votes

My code is 

  DBCollection collection = db.getCollection("volume");
  DBCursor cursor = collection.find();
  DBObject resultElement = cursor.next();
  Map resultElementMap = resultElement.toMap();
  System.out.println(resultElementMap);

And the result is:

{_id=521b509d20954a0aff8d9b02, title={ "text" : "Volume Of Work Orders" , "x" : -20.0}, xAxis={ "title" : { "text" : "2012 "} , "categories" : [ "Jan" , "Feb" , "Mar" , "Apr" , "May" , "Jun" , "Jul" , "Aug" , "Sep" , "Oct" , "Nov" , "Dec"]}, yAxis={ "min" : 1000.0 , "max" : 7000.0 , "title" : { "text" : "Volume(K)"} , "plotLines" : [ { "label" : { "text" : "Average" , "x" : 25.0} , "color" : "black" , "width" : 2.0 , "value" : 30.0 , "dashStyle" : "solid"}]}, legend={ "backgroundColor" : "#FFFFFF" , "reversed" : true}, series=[ { "name" : "Volume" , "showInLegend" : false , "data" : [ 2909.0 , 3080.0 , 4851.0 , 3087.0 , 2960.0 , 2911.0 , 1900.0 , 3066.0 , 3029.0 , 5207.0 , 3056.0 , 3057.0]}]}

I need to remove _id from the result. I understand i need to play around with collection.find(), but please can anyone help me? Am not able to get sesired result

2
javamongodb

2 Answers

6
votes

Two options:

You can remove the "_id" field from the map created:

...
resultElementMap.remove("_id");
System.out.println(resultElementMap);

Or you can ask the query results to not include the _id field:

DBObject allQuery = new BasicDBObject();
DBObject removeIdProjection = new basicDBObject("_id", 0);

DBCollection collection = db.getCollection("volume");
DBCursor cursor = collection.find(allQuery, removeIdProjection);
DBObject resultElement = cursor.next();
Map resultElementMap = resultElement.toMap();
System.out.println(resultElementMap);

See the documentation on projections for all of the details.

0
votes

Another option to consider, if you are reading the results iteratively, is doing something like this:

final FindIterable<Document> foundResults = collection.find();
for (final Document doc : foundResults) {
    doc.remove("_id");
    // doc.toJson() no longer has _id
}