MongoDB - strange behaviour of query

Question

I have this two documents in my mongoDB database:

db.DocumentFile.find().pretty()
{
"_id" : ObjectId("587f39910cc0fec092bdb10c"),
"_class" : "com.smartinnotec.legalprojectmanagement.dao.domain.DocumentFile",
"fileName" : "DocumentFile1",
"ending" : "jpg",
"projectId" : "587f39910cc0fec092bdb10b",
"active" : true,
"userIdBlackList" : [
    "587f39910cc0fec092bdb10a"
]
}
{
"_id" : ObjectId("587f39910cc0fec092bdb10d"),
"_class" : "com.smartinnotec.legalprojectmanagement.dao.domain.DocumentFile",
"fileName" : "DocumentFile2",
"ending" : "jpg",
"projectId" : "587f39910cc0fec092bdb10b",
"active" : true,
"userIdBlackList" : [ ]
}

I have this code in order to get amount of query:

final Query query = new Query();
query.addCriteria(Criteria.where("‌​userIdBlackList").nin(userId));

final Long amount = mongoTemplate.count(query, DocumentFile.class);
return amount.intValue();

The amount is 2 in this case what is wrong - it should be 1. The query in Query object looks like this:

Query: { "‌​userIdBlackList" : { "$nin" : [ "587f39910cc0fec092bdb10a"]}}

If I copy this query and made a query for the mongodb console like this:

db.DocumentFile.find({ "‌​userIdBlackList" : { "$nin" : [ "587f39910cc0fec092bdb10a"]}}).pretty()

I get an amount of two, what if wrong because one document includes 587f39910cc0fec092bdb10a in userIdBlackList -> it should be one.

With this query command:

db.DocumentFile.find({userIdBlackList: { "$nin": ["587f39910cc0fec092bdb10a"] } }).pretty();

I get the right result, I am really confused at the moment. Does anyone have any idea? Maybe the problem ist that one time userIdBlackList is with quotation mark ("userIdBlackList") and the other time it isn't.

Answer 1

I think the problem is with the unintentional formatting picked up for "userIdBlackList" . Your string is interpreted with non printing characters in the "??userIdBlackList" for all your search queries. I see little transparent square boxes when I copy your queries to mongo shell.

That tells me their is some encoding issue. Clear that formatting and see if that helps you.

Both $ne and $nin should work!