1.将集合中某字段抽取去重为集合
List<String> pillarsSidList = sdPillarsInstalls.stream().map(SdPillarsInstall::getPillarsSid).distinct().collect(Collectors.toList());
2.将集合中某字段提取为MAP
Map<Long, NyNybtPurchaseInfoReport> purchaseOrderIdMap = purchaseOrderList.stream().collect(Collectors.toMap(NyNybtPurchaseInfoReport::getId, Function.identity()));
3.将集合中某字段提取为集合
List<String> detailIdList = childrenList.stream().map(NyNybtSubsidyGatherReportDetail::getDetailIds).collect(Collectors.toList());
4.将集合中某字段提取进行拼接成字符串
String orderNumberStr = purchaseOrderRepeatList.stream().map(NyNybtPurchaseInfoReport::getOrderNumber).collect(Collectors.joining(","));
5.将集合中某字段提取为MAP<String,List>
Map<String, List<NyNybtPurchaseInfoReport>> map = purchaseOrderList.stream().collect(Collectors.groupingBy(NyNybtPurchaseInfoReport::getPurchaserSid));