java练习生 - 常用list 操作

   新建：

List<ProcessSyncPO> needSyncDataList = new ArrayList<>();
数组转List

List<String> excludeLoanKind = Arrays.asList(unGenerateExcLoanKind.split(","));

选择单列并排序，最后输出为List：

List<String> loansideList = statistics.stream().map(x -> x.getLoanSideName()).distinct().sorted().collect(Collectors.toList());

按照某列进行排序，最后输出为List：

fundWarningCounts.stream().sorted(Comparator.comparing(FundWarningCount::getCount).reversed()).collect(Collectors.toList());

查询满足条件的记录：

statistics.stream().filter(x -> loanSide.equals(x.getLoanSideName()) && loanKind.equals(x.getLoanKindName())).collect(Collectors.toList());

查询满足条件的数量：

statistics.stream().filter(x -> loanSide.equals(x.getLoanSideName()) && x.getCreateTime().toLocalDate().isBefore(LocalDate.parse(pivotalDate))).count();

分组：

Map<Long, List<SyncRequestEntity>> resultList = requests.stream().collect(Collectors.groupingBy(SyncRequestEntity::getSyncId));

分组后获取一列：

Map<Long, List<Long>> resultList = requests.stream().collect(Collectors.groupingBy(SyncRequestEntity::getSyncId, Collectors.mapping(SyncRequestEntity::getRequestId, Collectors.toList())));