Spring data mongodb check inside array whether value presents - mongodb

Question

I want to fetch all documents in which readBy array has suppose "2" value using spring data API.
Please help me.
My JSON in Mongodb is like this.
{
"_id" : ObjectId("52c14eb92f7ceb854e445354"),
"attachments" : [{
"fileMongoId" : "52c14eb82f7ceb854e44534b",
"fileName" : "Desert.jpg",
"fileSize" : "0 MB",
"fileType" : "image/jpeg"
}, {
"fileMongoId" : "52c14eb82f7ceb854e445350",
"fileName" : "Hydrangeas.jpg",
"fileSize" : "0 MB",
"fileType" : "image/jpeg"
}],
"from" : NumberLong(2),
"fromName" : "xyz",
"hasAttachment" : true,
"message" : "Hi all\r\n",
"read" : 1,
"readBy" : ["2", "3"],
"sentTime" : NumberLong("1388400312645"),
"sentType" : 2,
"subject" : "Hi",
"to" : [{
"toId" : "3",
"toName" : "pqr"
}, {
"toId" : "2",
"toName" : "xyz"
}]
}
Code to generate query
Username is string which I want to check whether it is present in readBy array or not
readBy is array of String
Query query = new Query();
Update update = new Update();
Criteria criteria = new Criteria();
if (read) {
// criteria = Criteria.where(username).in("readBy");
query.addCriteria(criteria.andOperator(Criteria.where("to.toId")
.in(toIdList)));
} else {
// criteria = Criteria.where(username).nin("readBy");
update.addToSet("readBy", username);
query.addCriteria(criteria.andOperator(Criteria.where("to.toId")
.in(toIdList)));
mongoTemplate.updateMulti(query, update, NewMessage.class);
}
query.fields().include("from");
query.fields().include("fromName");
query.fields().include("sentTime");
query.fields().include("hasAttachment");
query.sort().on("sentTime", Order.DESCENDING);
newMessages = mongoTemplate.find(query, NewMessage.class);