使用Java查找包含具有特定值的字段的所有mongo文档

Question

I am trying to use mongo's Java driver to read through a collection and only pull back documents with a field that is a range of values. An example of this would be if I had data like

{ "name" : "foo", "Color" : "white", "Date" : 20171116 }
{ "name" : "bar", "Color" : "black", "Date" : 20171115 }
{ "name" : "Jeff", "Color" : "purple", "Date" : 20171114 }
{ "name" : "John", "Color" : "blue", "Date" : 20171015 }

I would want to begin on 20171114 and end on 20171116 so I would do something like

DateFormat df = new SimpleDateFormat("yyyyMMdd");
String begin = "20171114";
String end   = "20171116";
Date startDate;
Date endDate;

Then I would need to convert the strings to a date and use a cursor like

try {
  startDate = df.parse(startDateString);
  endDate = df.parse(endDateString);
  BasicDBObject data = new BasicDBObject();
  data.put("Date", new BasicDBObject( new BasicDBOject( "$gte", startDate).append("$lte", endDate)));
} catch(ParseException e){
  e.printStackTrace
}

However when I do this it returns nothing.

Answer:

I was trying to compare a number to a date which doesn't work so I converted my begin & end string to integers by doing

Integer beginDate = Integer.valueOf(begin)
Integer endDate = Integer.valueOf(end)

and it worked.

Answer 1

I think you have saved values of Date as numbers. Please check your code once how you are saving and please let us know.

Considering that please try below by passing long values as

try {
  Long startDate = 20171114L;
  Long endDate = 20171116L;
  BasicDBObject data = new BasicDBObject();
  data.put("Date", new BasicDBObject( new BasicDBObject( "$gte", startDate).append("$lte", endDate)));
} catch(ParseException e){
  e.printStackTrace
}