黑马点评9——附近商户-GEO数据结构

GEO数据结构的基本用法

导入店铺数据结构到GEO

数据库里没法实现按照地理坐标排序等复杂的搜索功能，我们把数据存到redis中，只需要保存id和对应的x以及y的坐标，就可以在查询的时候，从redis中根据坐标查询出id， 然后根据id去数据库中查询要的数据。

    @Test
    public void loadShopData(){
        // 1. 查询店铺信息
        List<Shop> list = shopService.list();
        // 2. 把店铺信息分组， 按照typeId分组， id一致的放到一个集合
        Map<Long, List<Shop>> map = list.stream().collect(Collectors.groupingBy(Shop::getTypeId));
        // 3. 分批完成写入redis
        for (Map.Entry<Long, List<Shop>> entry : map.entrySet()) {
            // 3.1 获取类型id
            Long typeId = entry.getKey();
            String key = RedisConstants.SHOP_GEO_KEY + typeId;
            // 3.2 获取同类型的店铺的集合
            List<Shop> value = entry.getValue();
            List<RedisGeoCommands.GeoLocation<String>> locations = new ArrayList<>(value.size());
            // 3.3 写入redis GEOADD key经度， 维度 member
            for (Shop shop : value) {
//                stringRedisTemplate.opsForGeo().add(key, new Point(shop.getX(), shop.getY()), shop.getId().toString());  // 效率低
                locations.add(new RedisGeoCommands.GeoLocation<>(
                        shop.getId().toString(),
                        new Point(shop.getX(), shop.getY())
                ));
            }
            stringRedisTemplate.opsForGeo().add(key, locations);  // 批量存入
        }
    }

实现附件商户功能

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.data</groupId>
                    <artifactId>spring-data-redis</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>io.lettuce</groupId>
                    <artifactId>lettuce-core</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-redis</artifactId>
            <version>2.6.2</version>
        </dependency>
        <dependency>
            <groupId>io.lettuce</groupId>
            <artifactId>lettuce-core</artifactId>
            <version>6.1.8.RELEASE</version>
        </dependency>

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        // 1. 是否需要根据坐标查询
        if(x == null || y == null){
            // 不需要坐标查询、按数据库查询
            Page<Shop> page = query().eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            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. 查询redis、按照距离排序、分页. 结果：shopId， distance
        String key = RedisConstants.SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().search(key,
                GeoReference.fromCoordinate(x, y),
                new Distance(5000),
                RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end));  // 这里只能传入end， 返回的是0 - end， 我们接收后在手动分页
        // 4. 解析出id
        if(results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> content = results.getContent();
        if(content.size() <= from){
            // 没有下一页
            return Result.ok(Collections.emptyList());
        }
        // 4.1 截取从from到end部分
        List<Long> ids = new ArrayList<>(content.size());
        Map<String, Distance> distanceMap = new HashMap<>(content.size());
        content.stream().skip(from).forEach(result -> {
            // 4.2 获取店铺id
            String shopId = result.getContent().getName();
            ids.add(Long.valueOf(shopId));
            // 4.3 获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopId, distance);
        });
        // 5. 根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        // 6. 返回
        return Result.ok(shops);
    }