Question

我正在使用套接字处理服务器/客户端战舰游戏。项目的一部分需要在客户端进行输入验证以输入磁贴位置。用户应该输入一个字母A-E和一个数字1-5，而现在如果你输入一些无效的东西，它似乎会冻结。任何帮助将非常感谢，提前感谢！

            do{
            System.out.println("------------------------------------------------------------------------------------------------"); 
            System.out.println("Please type in a board position in the format of a letter followed by number, such as 'A1'. "); 
            Scanner sc = new Scanner(System.in);  
            String BoardChoice = sc.next();  
            if(BoardChoice.equals("A1" ) || BoardChoice.equals("B1" ) || BoardChoice.equals("C1" ) || BoardChoice.equals("D1" ) || BoardChoice.equals("E1" ) || 
               BoardChoice.equals("A2" ) || BoardChoice.equals("B2" ) || BoardChoice.equals("C2" ) || BoardChoice.equals("D2" ) || BoardChoice.equals("E2" ) || 
               BoardChoice.equals("A3" ) || BoardChoice.equals("B3" ) || BoardChoice.equals("C3" ) || BoardChoice.equals("D3" ) || BoardChoice.equals("E3" ) || 
               BoardChoice.equals("A4" ) || BoardChoice.equals("B4" ) || BoardChoice.equals("C4" ) || BoardChoice.equals("D4" ) || BoardChoice.equals("E4" ) || 
               BoardChoice.equals("A5" ) || BoardChoice.equals("B5" ) || BoardChoice.equals("C5" ) || BoardChoice.equals("D5" ) || BoardChoice.equals("E5" ))
            {
                flagtoo = false;
                writer.writeUTF(BoardChoice); 
            }
            else
            {
                System.out.println("Invalid Input Please re-enter!");
            }
            }while(flagtoo);

Answer 1

我建议您分别使用charAt分析每个字符，然后请尊重变量命名约定。像

这样的东西

boolean valid = false;
String boardChoice = sc.nextLine(); // <-- not next
if (boardChoice.length() == 2) {
    char col = boardChoice.charAt(0);
    char row = boardChoice.charAt(1);
    // The parenthesis here are just for clarity.
    valid = ((col >= 'A' && col <= 'E') && (row >= '1' && row <= '5'));
}

Answer 2

另一方面，我的建议是建议使用一种模式来实现正则表达式，该模式允许您匹配第一个char alpha（无论大小写）后跟一个数字，两者都在a→e和1→5

的范围内

    Scanner sc = new Scanner(System.in);

    System.out.println("Please type in a ....y number, such as 'A1'. ");

    do {
        inp = sc.nextLine();
        if (inp.matches("^[a-eA-E1-5]{0,2}")) {
            inpArr[k++] = inp;

        } else {
            System.out.println("invalid input");
        }
    } while (k < numberOfElements);

    System.out.println(Arrays.toString(inpArr));

Java条目验证

2 个答案: