java8stream流特性运用实例

List<PostSchoolResp> postList = newYearActivityMapper.getPostList(topicIdList, activity.getStartTime(), activity.getEndTime(),1);
List<PostSchoolResp> postLists = new ArrayList<>();

  Collections.sort(postLists, Comparator.comparing(PostSchoolResp::getCreateTime).reversed());
            List<PostSchoolResp> postListFOUR = postLists.stream().limit(4).collect(Collectors.toList());
            log.info("f数量："+postList.size());
            if (! postListFOUR.isEmpty()){
                postListFOUR.forEach(PostSchoolResps->{
                    PostSchoolResps.setIcon(JPIcon);
//删除集合中重复数据
                    postList.removeIf(PostSchoolResp->PostSchoolResp.getId().equals(PostSchoolResps.getId()));
//                    List<PostSchoolResp> postListNw = postList.stream().
//                            filter(PostSchoolResp -> (! PostSchoolResp.getId().equals(PostSchoolResps.getId()))).collect(Collectors.toList());
                });
            }
            log.info("ff数量："+postList.size());
//            BeanUtils.copyProperties(postListFOUR,postList);
            postListFOUR.addAll(postList);
//            List<PostSchoolResp> postListTEN = postLists.stream().limit(10).collect(Collectors.toList());
            log.info("fou数量："+postListFOUR.size());
            List<PostSchoolResp> postListLimit = postListFOUR.stream().skip((pageNum-1)*pageSize).limit(pageSize).
                    collect(Collectors.toList());
            return BaseResponse.buildSuccess("success", postListLimit);‘’

---------------------分页问题：

public PageInfo<HasDeliverResp> getHasDeliveredList(HasDeliverSearchReq hasDeliverSearchReq) {
    PageHelper.startPage(hasDeliverSearchReq.getPageNum(),hasDeliverSearchReq.getPageSize());
    Page<HasDeliverResp> hasDeliveredList = tOrderLocalSpeMapperExt.getHasDeliveredList(hasDeliverSearchReq);
    int total = (int) new PageInfo<>(hasDeliveredList).getTotal();
    PageInfo<HasDeliverResp> pageInfo = new PageInfo<HasDeliverResp>(hasDeliveredList);
    pageInfo.setTotal(total);

return pageInfo;