使用MongoDB实现地理位置的更新和搜索附近的人

MongoDB 地理索引

地理信息索引分为两类：2D平面索引，2DSphere球面索引。在2D索引里面基本上能够保存的信息都是坐标，而且坐标保存的就是经纬度坐标。

具体的应用场景在：微信的摇一摇，大众点评等查询附近的住宿地。滴滴、膜拜、OFO等基于位置进行查询的场景都可以使用MongoDB的位置索引。下面是使用的实例，在dubbo层进行一层业务封装

地理位置之dubbo接口实现

客户端检测用户的地理位置，当变化大于500米时或每隔5分钟，向服务端发送地理位置。

定义pojo

package com.tanhua.dubbo.server.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.bson.types.ObjectId;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.geo.GeoJsonPoint;
import org.springframework.data.mongodb.core.index.CompoundIndex;
import org.springframework.data.mongodb.core.index.Indexed;
import org.springframework.data.mongodb.core.mapping.Document;

@Data
@NoArgsConstructor
@AllArgsConstructor
@Document(collection = "user_location")
//指定我们UserLocation这个实例中使用的是2dsphere二维球面的索引
@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

}

定义dubbo接口

package com.tanhua.dubbo.server.api;

public interface UserLocationApi {

    /**
     * 更新用户地理位置
     *
     * @return
     */
    String updateUserLocation(Long userId, Double longitude, Double latitude, String address);

}

编写实现

package com.tanhua.dubbo.server.api;

import com.alibaba.dubbo.config.annotation.Service;
import com.tanhua.dubbo.server.pojo.UserLocation;
import org.bson.types.ObjectId;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.geo.GeoJsonPoint;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.data.mongodb.core.query.Update;

@Service(version = "1.0.0")
public class UserLocationApiImpl implements UserLocationApi {

    @Autowired
    private MongoTemplate mongoTemplate;

    @Override
    public String updateUserLocation(Long userId, Double longitude, Double latitude, String address) {

        UserLocation userLocation = new UserLocation();
        userLocation.setAddress(address);
        userLocation.setLocation(new GeoJsonPoint(longitude, latitude));
        userLocation.setUserId(userId);

        Query query = Query.query(Criteria.where("userId").is(userLocation.getUserId()));
        UserLocation ul = this.mongoTemplate.findOne(query, UserLocation.class);
        if (ul == null) {
            //新增----mongodb中没有该用户数据
            userLocation.setId(ObjectId.get());
            userLocation.setCreated(System.currentTimeMillis());
            userLocation.setUpdated(userLocation.getCreated());
            userLocation.setLastUpdated(userLocation.getCreated());

            this.mongoTemplate.save(userLocation);

            return userLocation.getId().toHexString();
        } else {
            //更新
            Update update = Update
                    .update("location", userLocation.getLocation())
                    .set("updated", System.currentTimeMillis())
                    .set("lastUpdated", ul.getUpdated());
            this.mongoTemplate.updateFirst(query, update, UserLocation.class);
        }

        return ul.getId().toHexString();
    }
    
}

地理位置之APP服务接口实现

前端使用的是百度的地图，向后端传送经、纬度以及地址，后端调用dubbo进行地理位置更新。

Controller层

package com.tanhua.server.controller;
import com.tanhua.server.service.BaiduService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.Map;

@RestController
@RequestMapping("baidu")
public class BaiduController {

    @Autowired
    private BaiduService baiduService;

    /**
     * 更新位置
     *
     * @param param
     * @return
     */
    @PostMapping("location")
    public ResponseEntity<Void> updateLocation(@RequestBody Map<String, Object> param) {
        try {
            Double longitude = Double.valueOf(param.get("longitude").toString());
            Double latitude = Double.valueOf(param.get("latitude").toString());
            String address = param.get("addrStr").toString();

            Boolean bool = this.baiduService.updateLocation(longitude, latitude, address);
            if (bool) {
                return ResponseEntity.ok(null);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
    }
}

Service层

package com.tanhua.server.service;
import com.alibaba.dubbo.config.annotation.Reference;
import com.tanhua.dubbo.server.api.UserLocationApi;
import com.tanhua.server.pojo.User;
import com.tanhua.server.utils.UserThreadLocal;
import org.springframework.stereotype.Service;

@Service
public class BaiduService {

    @Reference(version = "1.0.0")
    private UserLocationApi userLocationApi;

    public Boolean updateLocation(Double longitude, Double latitude, String address) {
        try {
            User user = UserThreadLocal.get();
            this.userLocationApi.updateUserLocation(user.getId(), longitude, latitude, address);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

}

搜索附近的人

//根据userId查找用户位置
    @Override
    public UserLocationVo queryByUserId(Long userId) {
        Query query = Query.query(Criteria.where("userId").is(userId));
        UserLocation one = mongoTemplate.findOne(query, UserLocation.class);
        if (null != one) {
            return UserLocationVo.format(one);
        }
        return null;
    }

    @Override
    public List<UserLocationVo> queryUserFromUserLocation(Double x, Double y, Integer range) {
        //找到中心点
        GeoJsonPoint geoJsonPoint = new GeoJsonPoint(x, y);
        //半径---Metric为接口，里面传入他的具体实现类
        Distance distance = new Distance(range / 1000, Metrics.KILOMETERS);
        //画圆
        Circle circle = new Circle(geoJsonPoint, distance);
        Query query = Query.query(Criteria.where("location").withinSphere(circle));
        List<UserLocation> userLocations = mongoTemplate.find(query, UserLocation.class);
        if (userLocations != null) {
            return UserLocationVo.formatToList(userLocations);
        }
        return null;
    }