从mongodb中的$ geoNear聚合获取距离字段

Question

I have the following aggregation command in my Spring project:

NearQuery query = NearQuery.near(longitude,latitude).maxDistance(distance).spherical(true);
agg = newAggregation(
                geoNear(query, "distance"),
                unwind("rate"),
                group("id")
                        .first("name").as("name")
                        .sum("$rate.general_rate").as("rate")
                        .count().as("num_rates")                                                                                        
        );

But when i made the mapped with my class, the distance field(from geoNear) is not exist. How can i pass in pipeline the distance to appear with others groups fields?

Answer 1

I faced the same :)

The answer is in your question..

geoNear(query, "distance"),

The above line will look for the property distance (type Double in case of Point) in the class which you are trying to aggregate the result.

Eg., output "distance" : 420.82602810248557 (in meters )