java8 LIst操作

java 8           
1, 逗号拼接 字符串转List
String biodId = reqVo.getBidIds();
List<Long> bidIdList = Arrays.asList(biodId.split(",")).stream().map(s -> Long.parseLong(s.trim())).collect(Collectors.toList());


2，List去重
List<Long> bidIdList = bidIdList.stream().distinct().collect(Collectors.toList());


3，filter过滤
List<StudyListVO> reduceList = studyAllList.stream().filter((StudyListVO studyListVO) -> allList.contains(studyListVO.getId())).collect(Collectors.toList());

filter筛选菜单ID=1的列表
List<MenuVo> havaList = menuVoList.stream().filter((MenuVo menuVo) -> menuVo.getId()==1).collect(Collectors.toList());


4,只取集合中某个字段组成新集合
List<Group> groupList = groupBiz.getGroupByUserId(String.valueOf(temp.getId())) ;

List<Long> groupIdList = groupList.stream().map(Group::getId).collect(Collectors.toList());