根据list里面对象的某个特定属性排序，若属性值为空的处理

Collections.sort(fileRecordDOList, Comparator.comparing(FileRecordDO::getOperateTime).reversed());

reversed()逆序排序,从大到小

若排序的属性值有空值，以上方法会报错，需要使用以下方法
升序：从小到大排序

 
Collections.sort(userList, new Comparator<User>() {
    @Override
    public int compare(User o1, User o2) {
        //若有空值可以在这里赋值
        return o1.getName().compareTo(o2.getName());
    }
});

降序：从大到小排序

Collections.sort(userList, new Comparator<User>() {
    @Override
    public int compare(User o1, User o2) {
        //若有空值可以在这里赋值
        return o2.getName().compareTo(o1.getName());
    }
});

多条件排序

            Collections.sort(recentModifyPredictLogDTOList, new Comparator<RecentModifyPredictLogDTO>() {
                @Override
                public int compare(RecentModifyPredictLogDTO o1, RecentModifyPredictLogDTO o2) {
                    if (o2.getPredictUpdateCount().compareTo(o1.getPredictUpdateCount()) == 1) {
                        return 1;
                    } else if (o2.getPredictUpdateCount().compareTo(o1.getPredictUpdateCount()) == -1) {
                        return -1;
                    } else if (o2.getPredictUpdateCount().compareTo(o1.getPredictUpdateCount()) == 0) {
                        // 如果成交套数相等的话就按照响应速度升序
                        if (o2.getPredictRealName().compareTo(o1.getPredictRealName()) == -1) {
                            return 1;
                        } else if (o2.getPredictRealName().compareTo(o1.getPredictRealName()) == 1) {
                            return -1;
                        } else if (o2.getPredictRealName().compareTo(o1.getPredictRealName()) == 0) {
                            if (o2.getStockShortName().compareTo(o1.getStockShortName()) == -1) {
                                return 1;
                            } else if (o2.getStockShortName().compareTo(o1.getStockShortName()) == 1) {
                                return -1;
                            } else if (o2.getStockShortName().compareTo(o1.getStockShortName()) == 0) {
                                return 0;
                            }
                        }
                    }
                    return 0;
                }
            });