java中对list集合进行分组

Map<String, List<HealthImport>> excelIdCardNull = importList.stream()
                .filter(temp -> temp.getIdcard() == null)
                .collect(Collectors.groupingBy(
                        p -> p.getIdcard()+'_'+p.getName()));

List<HealthImport> userHealthImport = excelMap.values().stream().map(p -> p.get(0)).collect(Collectors.toList());
        

List<RetAnswerDTO> appointMessages = getSchoolCheckAnswerDetails(QueryChildBodyCheckDTO.builder()
                .beginDate(LocalDateUtil.localDate2Date(LocalDate.now().minusDays(60))).build(),userHealthImport);