好的,我想要做的是找到在聚合管道中添加 $geoNear 的正确方法。我设法通过在聚合管道列表中添加 org.bson.Document 来做到这一点,但我认为应该有一种更清晰的方法来使用最新的官方 mongoDB Java-Driver 来实现它。例如,为了对 $group、$project、$match 执行此操作,mongoDB Java-Driver 提供了 Aggregates 类,相关调用为:
Aggregates.group
、Aggregates.project
、Aggregates.match
。我正在寻找的是类似:Aggregates.geoNear
,这是不存在的。我的示例代码如下所示:
createDocumentCollection()
.aggregate(
Arrays.asList(
// geoNear spherical geometry for 2d sphere
new Document("$geoNear", new Document()
.append("near", new Document()
.append("$geometry", new Document()
.append("type", "Point")
.append("coordinates", Arrays.asList(longitude, latitude)))
.append("$maxDistance", maxDistance))
.append("key", "avgGeoPoint")
.append("distanceField", "dist.calculated")),
// group
Aggregates.group("$mmsi",
Accumulators.first("mmsi", "$mmsi"),
Accumulators.first("vesselName", "$vesselName"),
Accumulators.first("shipType", "$shipType")),
// projection
Aggregates.project(Projections.fields(
Projections.excludeId(),
Projections.include("mmsi", "vesselName", "shipType"))),
// skip
Aggregates.skip(options.getSkip()),
// limit
Aggregates.limit(options.getLimit())))
.map(ModelExtractor::extractPlainVessel)
.forEach((Consumer<PlainVessel>) nearVessels::add);
我要替换的部分是这样的:
new Document("$geoNear", new Document()
.append("near", new Document()
.append("$geometry", new Document()
.append("type", "Point")
.append("coordinates", Arrays.asList(longitude, latitude)))
.append("$maxDistance", maxDistance))
.append("key", "avgGeoPoint")
.append("distanceField", "dist.calculated"))