mongoDB查询某个经纬度附近的用户

需求：获取某个点100m内的用户 数据库：mongoDB 语言：JAVA 1.地理位置数据以GeoJSON 的格式存储的

loc : { type : "Point", coordinates : [lng, lat] }

查询地理位置用到 geoWithin，可以查询多边形的地理位置信息，地球接近圆形，这里用到 centerSphere， 查询语句为

{ location field: { $geoWithin: { $centerSphere: [ [ x, y ], radius] } } }

x,y为中心点的经纬度，radius为距离中心点的距离，$centerSphere 使用弧度(radians)作为距离 距离与弧度之间的转换： distance to radians: divide the distance by the radius of the sphere (e.g. the Earth) in the same units as the distance measurement. radians to distance: multiply the radian measure by the radius of the sphere (e.g. the Earth) in the units system that you want to convert the distance to. 地球赤道的半径为3963.2 miles， 即 6378.1 kilometers， 只查找100m范围内，则radius为100/6378100。 参考信息： geowithin centerSphere calculate distances

Coordinates中数据类似如下：

{ "_id" : ObjectId("58403433785509513efe3279"), "account" : "18520222222", "platform" : "android", "location" : { "type" : "Point", "coordinates" : [ 108.840974298098, 34.2789316522934 ] }, "collectTime" : 1480602671, "logTime" : 1480602675 }

JAVA代码，此处只写了unit test, 简单测试代码逻辑。实际使用需要做相应改动。

package mongo; import java.net.UnknownHostException; import java.util.ArrayList; import java.util.HashSet; import java.util.List; import org.bson.Document; import org.junit.Before; import org.junit.Test; import com.mongodb.BasicDBList; import com.mongodb.BasicDBObject; import com.mongodb.MongoClient; import com.mongodb.MongoClientOptions; import com.mongodb.MongoCredential; import com.mongodb.MongoException; import com.mongodb.ServerAddress; import com.mongodb.client.MongoCursor; import com.mongodb.client.MongoDatabase; public class CoordinatesTest { public static final String mgoHost = "127.0.0.1:27017"; public static final String mgoUser = "test"; public static final String mgoPwd = "123456"; public static final String mgoDB = "info"; private static MongoDatabase db = null; @SuppressWarnings("resource") public void initMongo() throws UnknownHostException, MongoException { MongoClientOptions.Builder build = new MongoClientOptions.Builder(); build.connectionsPerHost(50); build.threadsAllowedToBlockForConnectionMultiplier(50); build.maxWaitTime(1000*60*2); build.connectTimeout(1000*30); build.socketTimeout(1000*30); List<ServerAddress> seeds = new ArrayList<ServerAddress>(); seeds.add(new ServerAddress(mgoHost)); MongoCredential credentials = MongoCredential.createScramSha1Credential(mgoUser, mgoDB, mgoPwd.toCharArray()); List<MongoCredential> credentialsList = new ArrayList<MongoCredential>(); credentialsList.add(credentials); MongoClient mongoClient = new MongoClient(seeds, credentialsList, build.build()); db = mongoClient.getDatabase(mgoDB); } public static List<String> distinct(String coll, BasicDBObject query, String key) { List<String> list = new ArrayList<String>(); MongoCursor<Document> cursor = null; try { cursor = db.getCollection(coll).find(query).projection(new BasicDBObject(key, 1)).iterator(); if (cursor != null) { HashSet<String> set = new HashSet<String>(); while (cursor.hasNext()){ Document doc = cursor.next(); String val = doc.getString(key); if (!set.contains(val)) { set.add(val); } } list.addAll(set); } } catch (Throwable e) { System.err.println("coll:"+coll+", query:"+query+", key:"+key+", occur exception: " + e.getMessage()); } finally { if (cursor != null) { cursor.close(); } } return list; } public static List<String> getAccountsByLocation(double longitude, double latitude, double radius) { BasicDBList point = new BasicDBList(); point.add(longitude); point.add(latitude); Double distance = radius/6378100; BasicDBList centerSphere = new BasicDBList(); centerSphere.add(point); centerSphere.add(distance); BasicDBObject location = new BasicDBObject("$geoWithin", new BasicDBObject("$centerSphere", centerSphere)); BasicDBObject query = new BasicDBObject("location", location); List<String> list = new ArrayList<String>(); try { list = CoordinatesTest.distinct("Coordinates", query, "account"); } catch (MongoException e) { System.err.println(e.getMessage()); } return list; } @Before public void init() throws Exception { initMongo(); } @Test public void test1() { List<String> accountList = getAccountsByLocation(113.941892, 22.50986, 100); System.out.println(accountList); } }