我有一个我转换为String的数组，我想按其中一个值排序

Question

我的Array中有4个对象。 lastName，firstName，fighterKills，motherShipKills。我想要的是能够通过其中一个对象对其进行排序。 （按字母顺序或数字表示）。我将Array转换为String。我应该在转换之前或之后进行排序。

import java.util.Scanner;
import java.util.ArrayList;
import java.util.Arrays;


public class SpaceInvaders {

    public SpaceInvaders() {
        addData(lastName, firstName, fighterKills, motherShipKills);
        sortBy();
        print();
    }

    ArrayList<Player> players = new ArrayList<Player>();
   String toString="";

   Scanner scan = new Scanner(System.in);
   int x = 10;
   String lastName;
   String firstName;
   int fighterKills;
   int motherShipKills;

  public void addData (String lastName, String firstName, int figherKills, int motherShipKills) {
        int x = 10;
        System.out.println("Welcome to Space Invaders!");
   for(int i = 0; i < x; i++) {

       System.out.println("Please Enter Last Name or the name of your text file or if you are done entering please enter 'done': ");

       lastName = scan.nextLine();

       if(lastName.equals("done")) {
           for (Player player : players) {
                    System.out.println(players);
                    break;
                }
                break;
            }
        else {
           System.out.println("Please Enter First Name: ");
           firstName = scan.nextLine();
           System.out.println("Please Enter Fighter Kills: ");
           fighterKills = scan.nextInt();
           System.out.println("Please Enter Mothership Kills: ");
           motherShipKills = scan.nextInt();
           Player player = new Player(lastName, firstName, fighterKills, motherShipKills);
           players.add(player);
           String line;

           System.out.println(players);
           scan.nextLine();
        }
    }
    }


    public void sortBy () {
         System.out.println("How would you like this sorted? 'Last Name'-1, 'First Name'-2, 'Fighter Kills'-3 or 'Mothership Kills'-4? ");
         System.out.println("Please enter the number corresponding to the way you would like this sorted: ");
         int sortBy = scan.nextInt();

            if (sortBy == 1) {
                System.out.println("Finished");
            }

            if (sortBy == 2 ){ 
                System.out.println("Yee Buddy");
            }

             if (sortBy == 3) {
                 bestFighter();
                }

             if (sortBy == 4) {
                bestMotherShip();
            }
    }


        public String toString () {
            for (Player play : players) {
                toString += play.toString()+ "\n";
            }
            return toString;
        }

        public void print() {
        }

        public String bestFighter() {
        }

        public String bestMotherShip() {
            String bestMotherShip = "Working";
            System.out.println("Working");
            return bestMotherShip;
        }
        public static void main(String[] args) {
            SpaceInvaders tp = new SpaceInvaders();
             System.out.println(" LAST NAME " + "\t" + " FIRST NAME " + "\t" + " FIGHTER KILLS " + "\t" + " MOTHERSHIP KILLS "); 
             System.out.println(" -------------------------------------------------------------------");
             System.out.println( tp.toString());
            }
   }

所以我输入“Smith”，Bob“，”2“，24”然后“Joe”，“Shmo”，“3”，“15”。它会打印

Smith Bob 2 24

Shmo Joe 3 15

如果我希望它按照战斗机技能排序，它将改为

Shmo Joe 3 15

Smith Bob 2 24