Java对含有null的集合进行排序

上下翻飞的屁2023-10-23 10:47

1.原始comparator

java 复制代码

public static List<ReportVehicleVo> sortByBuildingPhaseAndFdeName(List<ReportVehicleVo> list){
        list.sort(new Comparator<ReportVehicleVo>() {
            @Override
            public int compare(ReportVehicleVo o1, ReportVehicleVo o2) {
                if (StringUtils.isBlank(o1.getVeBuildingPhase())){
                    return -1;
                }
                if (StringUtils.isBlank(o2.getVeBuildingPhase())){
                    return 1;
                }
                if (o1.getVeBuildingPhase().compareTo(o2.getVeBuildingPhase()) > 0){
                    return 1;
                }else if (o1.getVeBuildingPhase().compareTo(o2.getVeBuildingPhase()) < 0){
                    return -1;
                }else {
                    if (StringUtils.isBlank(o1.getFdeName())){
                        return -1;
                    }
                    if (StringUtils.isBlank(o2.getFdeName())){
                        return 1;
                    }
                    if (o1.getFdeName().compareTo(o2.getFdeName()) > 0){
                        return 1;
                    }else {
                        return -1;
                    }
                }
            }
        });
        return list;
    }

原始方法判空后再排序

2.优雅方式

java 复制代码

List<String> testingPlaceList = new ArrayList<>();
testingPlaceList.sort(Comparator.nullsFirst(Comparator.naturalOrder()));

下边一行代码执行完就排好序了，并且nullsFirst会把null值排到前边，如果你想排到后边就换成nullsLast，另外naturalOrder是正序，如果你想倒序就换成reverseOrder