java - 如何验证此 Java 代码的用户输入？

Question

我想验证以下内容:仅输入数字，小时必须 <=24，分钟必须 <60，并且用户必须在 hh:mm 之间键入“:”符号。

 int total; //Total Minutes
    String time; //Input from keyboard


    final Scanner T = new Scanner(System.in);

    System.out.print("Enter the time in HH:MM :");
    time = T.next();

    //Get the value before the ':'
    int hour = Integer.parseInt(time.substring(0, time.indexOf(':')));


    //Get the value after the ':'
    int minute =Integer.parseInt (time.substring((time.indexOf(':') + 1), time.length()));


    //Formula of the calculation
    total = hour * 60 + minute;


    //Display the final value
    System.out.println( time +" is " + total + " minutes.");

Answer 1

要进行验证，请使用正则表达式:

time.matches( "(?:[01][0-9]|2[0-3]):[0-5][0-9]" )

要转换，只需使用

int hour = Integer.parseInt(time.substring(0, 2));
int minute = Integer.parseInt(time.substring(3));