定义用户位置类：

　　MongoDB的 2dsphere索引支持查询在一个类地球的球面上进行几何计算，以GeoJSON对象或者普通坐标对的方式存储数据。

@Data
@NoArgsConstructor
@AllArgsConstructor
@Document(collection = "user_location")
@CompoundIndex(name = "location_index", def = "{'location': '2dsphere'}")
public class UserLocation implements java.io.Serializable{

    private static final long serialVersionUID = 4508868382007529970L;

    @Id
    private ObjectId id;
    @Indexed
    private Long userId; //用户id
    private GeoJsonPoint location; //x:经度 y:纬度
    private String address; //位置描述
    private Long created; //创建时间
    private Long updated; //更新时间
    private Long lastUpdated; //上次更新时间
}

　业务一：上报地理位置

　　　前端会传递用户地理位置信息

    /**
     * 上报地理位置
     * @param map
     * @return
     */
    @PostMapping("/location")
    public ResponseEntity saveLoca(@RequestBody Map map){
        Double longitude =Double.valueOf(map.get("longitude").toString()) ;
        Double latitude = Double.valueOf(map.get("latitude").toString());
        String addrStr = map.get("addrStr").toString();
        baiduService.update(longitude,latitude,addrStr);
        return ResponseEntity.ok(null);
    }

　　保存信息到mongoDB数据库

    @Override
    public boolean saveLoca(Double longitude, Double latitude, String addrStr, Long userId) {
        try {
//        查询用户地址
            Query query = Query.query(Criteria.where("userId").is(userId));
            UserLocation location = mongoTemplate.findOne(query, UserLocation.class);
//        进行判断
            if (location != null) {
    //            更新
                Update update = Update.update("location", new GeoJsonPoint(longitude, latitude))
                        .set("address", addrStr).set("lastUpdated", location.getUpdated())
                        .set("updated", System.currentTimeMillis());
                mongoTemplate.updateFirst(query, update, UserLocation.class);

            } else {
    //            保存
                location = new UserLocation();
                location.setAddress(addrStr);
                location.setCreated(System.currentTimeMillis());
                location.setLastUpdated(System.currentTimeMillis());
                location.setUpdated(System.currentTimeMillis());
                location.setUserId(userId);
                location.setLocation(new GeoJsonPoint(longitude, latitude));
                mongoTemplate.save(location);
            }
            return true;
        } catch (Exception exception) {
            exception.printStackTrace();
            return false;
        }
    }

　　业务二：查询附近的人

　　根据传递过来的信息进行查询

    /**
     * 获取周边陌生人
     * @param gender
     * @param distance
     * @return
     */

    @GetMapping("/search")
    public ResponseEntity search(String gender,
                                 @RequestParam(defaultValue = "1000") String distance){
        List<NearUserVo> nearUserVos = tanhuaService.queryNear(gender, distance);
        return ResponseEntity.ok(nearUserVos);
    }

　　根据条件进行查询

    /**
     * 查询周围人
     * @param distance
     * @return
     */
    @Override
    public List<Long> query(String distance, Long userId) {
//       获取当前用户位置
        Query query = Query.query(Criteria.where("userId").is(userId));
        UserLocation location = mongoTemplate.findOne(query, UserLocation.class);
//        按条件查询周边
        if (location==null){
            return null;
        }
//        设置圆心
        GeoJsonPoint point = location.getLocation();
//        设置半径
        Distance r = new Distance(Double.valueOf(distance) / 1000, Metrics.KILOMETERS);
//       画圆
        Circle circle = new Circle(point, r);
//        查询
        Query qu2 = Query.query(Criteria.where("location").withinSphere(circle));
        List<UserLocation> list = mongoTemplate.find(qu2, UserLocation.class);
//        返回id集合
        return CollUtil.getFieldValues(list, "userId", Long.class);
    }