Java如何在不匹配条件时重复语句

Question

如果用户输入与正确的格式不匹配，我试图让该程序重新启动。但是我不确定如何做到这一点。我已附上以下代码:

package weeek4;

import javax.swing.JOptionPane;


public class rollNumber {
public static void main(String[] args) { 

String input = JOptionPane.showInputDialog(null,"Enter your Roll Number in        this format **-***-*****");

if (input.matches("\\d{2}-\\d{3}-\\d{5}")) {
JOptionPane.showMessageDialog(null,"Thank you");
}
else {
    JOptionPane.showMessageDialog(null,"Invalid Number");
    }


}
}

Answer 1

这很容易。只需使用循环(重复代码块直到满足特定条件的语句)和标志变量(在本例中，k 检查while 循环)

package weeek4;

import javax.swing.JOptionPane;


public class rollNumber 
{
   public static void main(String[] args) 
   { 

      String input = JOptionPane.showInputDialog(null,"Enter your Roll Number in        this format **-***-*****");
      int k = 0;
      while (k!=1)
      {
         if (input.matches("\\d{2}-\\d{3}-\\d{5}")) {
            JOptionPane.showMessageDialog(null,"Thank you");
            k=1;
         }
         else
            JOptionPane.showMessageDialog(null,"Invalid Number");
      }


    }
}

希望我有帮助:)