Java將list或者list 集合根據指定字段排序

今天項目中用到了,特記錄一下

一. List<Map>

如果 item.get(sortField) 有時間,有數字的時候直接toString(),數組結果的排序結果可能不正確

List<Map<String, Object>> resourceCatalogFrontVoList = resourceMapper.selectPublishResourceCatalogList(keyWord, sysId, shareType, openAttribute,
                classifyId, resourceType, page);
        //排序
        Comparator<Map<String, Object>> comparator = Comparator.comparing(item -> item.get(sortField).toString());
        if (FrontConstant.SORT_TYPE_ASC == sortType){
            //升序
            resourceCatalogFrontVoList.sort(comparator);
        }else {
            resourceCatalogFrontVoList.sort(comparator.reversed());
        }
        //分頁
        return page.setRecords(resourceCatalogFrontVoList);

補充

if (FrontConstant.SORT_TYPE_ASC == sortType){
            //升序
            Collections.sort(resourceCatalogFrontVoList, Comparator.comparing(
                    item -> item.get(sortField).toString()));
        }else {
            Collections.sort(resourceCatalogFrontVoList, Comparator.comparing(
                    item -> item.get(sortField).toString(), Comparator.reverseOrder()));
        }

 

 

二.List<entity>

List<ResMessageVo> messageVoList = messageMapper.selectUnReadMessage(null, null, null, MessageConstant.MESSAGE_TYPE_MOUNT_RESOURCE_RESULT);

//排序

        Comparator<ResMessageVo> comparator = Comparator.comparing(item -> item.getCreateTime()); if (FrontConstant.SORT_TYPE_ASC == sortType){ //升序
 messageVoList.sort(comparator); }else { messageVoList.sort(comparator.reversed()); }