Java 身份证排序算法：根据年月日升序排序

import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.Scanner;

public class Main { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); int n = Integer.parseInt(scanner.nextLine()); ArrayList idList = new ArrayList<>(); for (int i = 0; i < n; i++) { String id = scanner.nextLine(); idList.add(id); } String command = scanner.nextLine(); if (command.equals("sort1")) { sortByIdDate(idList); } else if (command.equals("sort2")) { sortById(idList); } else { System.out.println("exit"); System.exit(0); } for (String id : idList) { System.out.println(id); } }

public static void sortByIdDate(ArrayList<String> idList) {
    Collections.sort(idList, new Comparator<String>() {
        @Override
        public int compare(String id1, String id2) {
            String date1 = id1.substring(6, 14);
            String date2 = id2.substring(6, 14);
            return date1.compareTo(date2);
        }
    });
}

public static void sortById(ArrayList<String> idList) {
    Collections.sort(idList);
}

}