如:
Class MdmOrgPostcodeEntity
{
String id,
String name
}
需要將List<MdmOrgPostcodeEntity> -->轉換成List<String>這樣方便根據ID批量刪除
List<String> list = functions.stream().map(MdmOrgFunctionEntity::getId).collect(Collectors.toList());
List<OrgGroupBuildOrg> 按照某個字段 分組
1 1
2 2
1 3
2 3
輸出: 1 List<>, 2 List
Map<String, List<OrgGroupBuildOrg>> destOrgListMap = destOrgListAll.stream().collect(Collectors.groupingBy(OrgGroupBuildOrg::getOrgGroupId));
根據某個字段去重
//根據userid去重 userList = userList.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(User :: getUserid))), ArrayList::new)); System.out.println(userList);