09 - GEO 附近商户#

客户端请求: GET /shop/of/type?typeId=1&x=116.4&y=39.9&current=1
                            │
                            ▼
                   ShopServiceImpl.queryShopByType()
                            │
              ┌─────────────┴──────────────┐
              │ 有坐标(x,y)?               │
              │                            │
         YES  ▼                       NO   ▼
    Redis GEO 查询                   MySQL 分页查询
         │                           (普通 type_id 过滤)
         ▼
    GEOSEARCH shop:geo:{typeId}
      BYLONLAT x y
      BYRADIUS 5000m
      WITHDISTANCE
      LIMIT {end}
         │
         ▼
    ┌────────────────────┐
    │ 结果: shopId + 距离 │
    │  skip(from) 跳过前页│
    │  → ids + distanceMap│
    └────────┬───────────┘
             │
             ▼
    MySQL: WHERE id IN (ids)
           ORDER BY FIELD(id, ...)
             │
             ▼
    设置每个 Shop 的 distance 字段
             │
             ▼
         返回 Result

@Override
public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
    // 1.无坐标 → 走数据库
    if (x == null || y == null) {
        Page<Shop> page = query()
                .eq("type_id", typeId)
                .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
        return Result.ok(page.getRecords());
    }

    // 2.计算分页参数
    int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
    int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

    // 3.Redis GEO 查询: 5km 半径内的商铺
    String key = SHOP_GEO_KEY + typeId;  // shop:geo:{typeId}
    GeoResults<RedisGeoCommands.GeoLocation<String>> results =
        stringRedisTemplate.opsForGeo().search(
            key,
            GeoReference.fromCoordinate(x, y),
            new Distance(5000),  // 5000米 = 5km
            RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs()
                .includeDistance()  // 返回距离
                .limit(end)        // 只取前 end 条
        );

    // 4.手动跳页: GEO 不支持 offset, 用 skip 模拟
    List<GeoResult<...>> list = results.getContent();
    if (list.size() <= from) {
        return Result.ok(Collections.emptyList()); // 无下一页
    }

    List<Long> ids = new ArrayList<>();
    Map<String, Distance> distanceMap = new HashMap<>();
    list.stream().skip(from).forEach(result -> {
        String shopIdStr = result.getContent().getName();
        ids.add(Long.valueOf(shopIdStr));
        distanceMap.put(shopIdStr, result.getDistance());
    });

    // 5.MySQL 查询完整信息 + 保持顺序
    String idStr = StrUtil.join(",", ids);
    List<Shop> shops = query().in("id", ids)
            .last("ORDER BY FIELD(id," + idStr + ")")
            .list();

    // 6.设置距离
    for (Shop shop : shops) {
        shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
    }
    return Result.ok(shops);
}