Sådan får du afstand - MongoDB Template Near-funktion

Du kan gøre det med geoNear-aggregation . I spring-data-mongodb GeoNearOperation repræsenterer denne sammenlægning.

Udvid eller opret arv Place klasse med felt, hvor du gerne vil have afstandsoplysninger (eksempel med arv):

public class PlaceWithDistance extends Place {
    private double distance;

    public double getDistance() {
        return distance;
    }

    public void setDistance(final double distance) {
        this.distance = distance;
    }
}

I stedet for Criteria med Query bruge aggregering. Andet argument for geoNear er navnet på det felt, hvor afstanden skal indstilles:

final NearQuery nearQuery = NearQuery
    .near(new Point(searchRequest.getLat(), searchRequest.getLng()));
nearQuery.num(5);
nearQuery.spherical(true); // if using 2dsphere index, otherwise delete or set false

// "distance" argument is name of field for distance
final Aggregation a = newAggregation(geoNear(nearQuery, "distance"));

final AggregationResults<PlaceWithDistance> results = 
    mongoTemplate.aggregate(a, Place.class, PlaceWithDistance.class);

// results.forEach(System.out::println);
List<PlaceWithDistance> ls = results.getMappedResults();

Bare for at gøre det nemmere - tilhørende importer:

import static org.springframework.data.mongodb.core.aggregation.Aggregation.geoNear;
import static org.springframework.data.mongodb.core.aggregation.Aggregation.newAggregation;

import org.springframework.data.mongodb.core.aggregation.Aggregation;
import org.springframework.data.mongodb.core.aggregation.AggregationResults;
import org.springframework.data.mongodb.core.aggregation.GeoNearOperation;
import org.springframework.data.mongodb.core.query.NearQuery;