如果第一个玩家输入了错误的命令，那么我怎么能这样做呢？

我正在尝试制作一个摇滚纸剪刀 - 蜥蜴游戏 . 我一直在学习if / else语句 . 我试图这样做，以便如果player1输入一个无效的命令，那么它将打印出“抱歉，这不是一个有效的命令”，就像使用else语句一样 . 如果两个玩家输入一个命令而一个是错误的，那么它是有效的，但如果只是玩家1的话 . 你能帮我搞清楚我应该做些什么吗？这是我的代码：

package csc212hw03;
    import java.util.Scanner;

    public class Main {

public static void main(String[] args) {
    String player1;
    String player2;
    String player1Choice;
    String player2Choice;
    String line;

           // “1” for Paper
    //“2” for Rock
    //“3” for Spock
    //“4” for Lizard
    //“5”for Scissors
   Scanner kb = new Scanner(System.in);
   System.out.println("Player 1, please enter your name:");
   player1 = kb.nextLine();

   System.out.println("Player 2, please enter your name:");
   player2 = kb.nextLine();

   System.out.println(player1 + ", please enter your command:");
   player1Choice = kb.nextLine();

   System.out.println(player2 + ", please enter your command:");
   player2Choice = kb.nextLine();

   if (player1Choice.equals("1") && player2Choice.equals("2")) {
       System.out.println(player1 + " wins! Paper covers Rock.");
       System.out.println("Thank you for playing.");
   } else if (player2Choice.equals("2") && player1Choice.equals("1")){
       System.out.println(player2 + " wins! Paper covers Rock.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("1")&& player2Choice.equals("1")) {
       System.out.println("Draw!");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("2")&& player2Choice.equals("2")) {
       System.out.println("Draw!");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("1")&& player2Choice.equals("3")) {
       System.out.println(player1 + " wins! Paper disproves Spock.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("3") && player2Choice.equals("1")) {
       System.out.println(player2 + " wins! Paper disproves Spock.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("3")&& player2Choice.equals("3"))  {
       System.out.println("Draw!");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("2") && player2Choice.equals("3")) {
       System.out.println(player2 + " wins! Spock vaporizes Rock.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("3") && player2Choice.equals("2")) {
       System.out.println(player1 + " wins! Spock vaporizes Rock.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("3") && player2Choice.equals("5")) {
       System.out.println(player1 + " wins! Spock smashes Scissors.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("5") && player2Choice.equals("3")) {
       System.out.println(player2 + " wins! Spock smashes Scissors.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("5") && player2Choice.equals("5")) {
       System.out.println("Draw!");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("2") && player2Choice.equals("5")) {
       System.out.println(player1 + " wins! Rock crushes Scissors.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("5") && player2Choice.equals("2")) {
       System.out.println(player2 + " wins! Rock crushes Scissors.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("2") && player2Choice.equals("4")) {
       System.out.println(player1 + " wins! Rock crushes Lizard.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("4") && player2Choice.equals("2")) {
       System.out.println(player2 + " wins! Rock crushes Lizard.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("3") && player2Choice.equals("4")) {
       System.out.println(player2 + " wins! Lizard poisons Spock.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("4") && player2Choice.equals("3")) {
       System.out.println(player1 + " wins! Lizard poisons Spock.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("5") && player2Choice.equals("1")) {
       System.out.println(player1 + " wins! Scissors cuts Paper.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("1") && player2Choice.equals("5")) {
       System.out.println(player2 + " wins! Scissors cuts Paper.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("5") && player2Choice.equals("4")) {
       System.out.println(player1 + " wins! Scissors decpitates Lizard.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("4") && player2Choice.equals("5")) {
       System.out.println(player2 + " wins! Scissors decapitates Lizard.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("5") && player2Choice.equals("5")) {
       System.out.println("Draw!");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("4") && player2Choice.equals("4")) {
       System.out.println("Draw!");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("4") && player2Choice.equals("1")) {
       System.out.println(player1 + " wins! Lizard eats Paper.");
       System.out.println("Thank you for playing.");
   } else if (player1Choice.equals("1") && player2Choice.equals("4")) {
       System.out.println(player2 + " wins! Lizard eats Paper.");
       System.out.println("Thank you for playing.");
   } else {
       System.out.println("I'm sorry, this is not a valid command.");
       System.out.println("Thank you for playing.");

   }
      }
    }