Firestore query by date range

Question

I need the help to query long collection with date range. See the below example document. I wanna query startTime field using date range.

Answer 1

Generic function to find documents in a collection by date range of specifics fields:

public List findDocsByDateRange(String collection, 
                                                       String fieldStartDate,
                                                       String fieldEndDate,
                                                       Date startDate, 
                                                       Date endDate) {
    ApiFuture querySnapshot = fireStore()
                    .collection(collection)
                    .whereGreaterThanOrEqualTo(FieldPath.of(fieldStartDate), startDate)
                    .whereLessThanOrEqualTo(FieldPath.of(fieldEndDate), endDate)
                    .get();
    return querySnapshot.get().getDocuments();
}

Packages:

import com.google.api.core.ApiFuture;
import com.google.cloud.firestore.DocumentSnapshot;
import com.google.cloud.firestore.FieldPath;
import com.google.cloud.firestore.Firestore;
import com.google.cloud.firestore.QueryDocumentSnapshot;
import com.google.cloud.firestore.QuerySnapshot;