copy 集合List

复制list集合
BeanUtil.copyToList(problemTypeList, ProblemTypeVo.class);


stream 根据属性拼接字符串
List<String> nameList = personList.stream().map(Person::getName).collect(Collectors.toList());

stream 分组

Map<String, List<ProblemUserVo>> collect = userVos.stream().collect(Collectors.groupingBy(ProblemUserVo::getProblemType));

根据name,sex两个属性去重
List<ProblemUserVo> unique = userVos.stream().collect(
        Collectors. collectingAndThen(
                Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(o -> o.getProblemType() + ";" + o.getCategory()))), ArrayList::new)
);