拉姆达Lambda表达式对list分页，获取list总页数

向右看齐 2024-04-08 08:29 71阅读 0赞

1：对集合进行分页

@Override
        public IPage<FreeEntity> queryFreeList(FreeQuery freeQuery) {
            String tag = redisTemplate.opsForHash().get("REDIS_DIC:af_server_suffix", freeQuery.getServerId()).toString();
            String freeListResult = (String) redisTemplate.opsForHash().get(GeneralConstant.FREELIST + freeQuery.getTenantId(),
                    freeQuery.getTenantId() + tag);
            List<FreeEntity> freeList = JSONObject.parseArray(freeListResult, FreeEntity.class);
            List<FreeEntity> entityList = freeList.stream().skip(freeQuery.getPageSize() * (freeQuery.getPageNum() - 1)).limit(freeQuery.getPageSize()).collect(Collectors.toList());
            Page<FreeEntity> freeEntityPage = new Page<>();
            //总条数
            freeEntityPage.setTotal(freeList.size());
            //列表
            freeEntityPage.setRecords(entityList);
            //当前页
            freeEntityPage.setCurrent(freeQuery.getPageNum());
            //行数
            freeEntityPage.setSize(freeQuery.getPageSize());
            //总页数
            freeEntityPage.setPages(getPages(freeList, freeQuery.getPageSize()));
            return freeEntityPage;
        }
    
        /**
         * 返回总页数
         *
         * @param obj
         * @param pageSize
         * @return
         */
        public int getPages(List<FreeEntity> obj, Integer pageSize) {
            int count = obj.size() / pageSize;
            if (obj.size() == 0) {
                return 0;
            }
            if (obj.size() <= pageSize) {
                return 1;
            } else if (count % pageSize == 0) {
                return count;
            } else {
                return count + 1;
            }
        }