尝试使用jtextfield捕获异常？

Question

I'm making a simple GUI where the user has to enter 2 random strings of numbers and when the done button is pushed it will output those 2 strings. But how do I do this with try-catch method so that the user only can use numbers otherwise it will catch exceptions?

This is my code:

public Panel() 
{
    label1 = new JLabel("first string: ");
    label2 = new JLabel("second string: ");
    field1 = new JTextField(38);
    field2 = new JTextField(3);
    button1 = new JButton("done");

    ButtonP buttonP = new ButtonP();
    button1.addActionListener(buttonP);

    this.add(label1);
    this.add(field1);
    this.add(label2);
    this.add(field2);
    this.add(button1);
}

private class ButtonP implements ActionListener
{   
    public void actionPerformed(ActionEvent e)  
    {
        System.out.println("String 1 " + field1.getText() + " and string 2 " + field2.getText());
    }
}

Answer 1

The isDigit(char) method may be useful for you.

 public void actionPerformed(ActionEvent e)  
{
   for(char c: field1.getText().toCharArray()) {
       if(!Character.isDigit(c)) throw new WhateverException();
   }
   //Repeat this for field2's text as well
   //do other things with the strings, at this point they are valid
}

Replace the WhateverException with any exception you need thrown there.