Java如何验证2个输入是否为浮点数

Question

我要用户输入2个浮点数，并且需要验证用户是否正确输入了2个浮点数。我正在使用“扫描程序”读取用户输入，并使用“ .hasNextFloat（）”来验证用户输入是否为浮点型。我的代码如下。但是我发现我编写的代码仅在第一次运行do..while循环时才验证用户的首次输入，因此，如果用户的输入为（字符+浮点数），则代码可以得出正确的结果。但是，如果用户的输入是（float + character），则它将崩溃，因为它将绕过do..while循环，并直接转到firstN = readInput1.nextFloat（）; secondN = readInput1.nextFloat（）;）。 因此，我想知道如何使用do ... while循环检查两个输入。谢谢！

public static void main(String[] args) {

    System.out.printf("Welcome to Lucy's Get 2 Floats Program! \n\n");

    Scanner readInput1 = new Scanner(System.in);

    float firstN;
    float secondN;

    do
    {       
    System.out.println("Please enter two floats separated by a space: ");
    while(!readInput1.hasNextFloat()) {  
        System.out.println("You have entered an invalid choice. Please try again:");
      readInput1.next(); 
      readInput1.next();
    }
    } while(!readInput1.hasNextFloat());    

    firstN = readInput1.nextFloat();
    secondN = readInput1.nextFloat();
    System.out.printf("You have entered two valid floats: %5.2f and %5.2f", firstN, secondN);

}

Answer 1

此代码有效，但我不知道这是否是最好/最有效的方法：

public static void main(String[] args) {

    System.out.printf("Welcome to Lucy's Get 2 Floats Program! \n\n");

    Scanner readInput1 = new Scanner(System.in);

    float firstN;
    float secondN;

    System.out.println("Please enter two floats separated by a space: ");
    boolean loop = true;
    while(loop) {
        if (readInput1.hasNextFloat()) {
            firstN = readInput1.nextFloat();
            if (readInput1.hasNextFloat()) {
                secondN = readInput1.nextFloat();
                System.out.printf("You have entered two valid floats: %5.2f and %5.2f", firstN, secondN);
                loop = false;
            } else {
                System.out.println("You have entered an invalid choice. Please try again:");
                readInput1.next();
            }
        } else {
            readInput1.next();
            readInput1.next();
            System.out.println("You have entered an invalid choice. Please try again:");
        }
    }

}