java对list的常用操作（排序，分组，去重）

1.去重

 public static ArrayList<OrganizationInfoBO> removeDuplicteUsers(ArrayList<OrganizationInfoBO> listOrganizationInfoBo) {
        Set<OrganizationInfoBO> setBo = new TreeSet<OrganizationInfoBO>(new Comparator<OrganizationInfoBO>() {
            @Override
            public int compare(OrganizationInfoBO o1, OrganizationInfoBO o2) {
                return o1.getId().compareTo(o2.getId());
            }
        });
        setBo.addAll(listOrganizationInfoBo);
        return new ArrayList<OrganizationInfoBO>(setBo);
    }

2.分组

Map<String, List<AttendRulesInfoBO>> group = resultBo(list对象).
stream().collect(Collectors.groupingBy
(AttendRulesInfoBO（list中VO）::getLateClass（VO中get方法）));

3.排序

            //按照条码类别倒序，条码编码正序排列
            Collections.sort(result, new Comparator<BarcodeManageVo>() {
                @Override
                public int compare(BarcodeManageVo bo1, BarcodeManageVo bo2) {
                    return bo2.getBatchCode().compareTo(bo1.getBatchCode());
                    //String的逆序排列
                }
            });