将JSON数组转化为List集合

假如我们向redis中存放了一个JSON数组，从中获取的时候需要将JSON数组转化为List集合，然后将List对象返回给前端。

1.引入hutool和fastjson依赖

        <!--hutool-->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.7.17</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.66</version>
        </dependency>

2.hutool的作用是使用JSONUtil类将数据库查到的List集合转化成JSON数组,存到redis中

List<ShopType> typeList = typeService.query().list();
String typeListJson = JSONUtil.toJsonStr(typeList);
stringRedisTemplate.opsForValue().set("shopList",typeListJson);

3.fastjson的JSONObject类作用是将JSON数组转换成List集合

String shopList = stringRedisTemplate.opsForValue().get("shopList");
List<ShopType> list = JSONObject.parseArray(shopList, ShopType.class);
return Result.ok(list);

完整代码：

    @GetMapping("list")
    public Result queryTypeList() {
        String shopList = stringRedisTemplate.opsForValue().get("shopList");
        if(StringUtils.isEmpty(shopList)){
            List<ShopType> typeList = typeService
                    .query().orderByAsc("sort").list();

            String typeListJson = JSONUtil.toJsonStr(typeList);
            stringRedisTemplate.opsForValue().set("shopList",typeListJson);
            return Result.ok(typeList);
        }
        List<ShopType> list = JSONObject.parseArray(shopList, ShopType.class);
        return Result.ok(list);
    }