通过GUI进行java输入输出测试

大家好，请告诉我在尝试运行此程序并获得

java.lang.NumberFormatException

错误时我错在哪里

 import javax.swing.*; 
 public class InputOutputTest { 
 public static void main(String[] args) { 
   //takes input through GUI 
   String input = JOptionPane.showInputDialog("Enternumber"); 
   int number = Integer.parseInt(input); 
   int square = number * number; 
   //Display square on console 
   System.out.println("square:" + square); 
   //Display square on GUI 
   JOptionPane.showMessageDialog(null, "square:"+ square); 
   System.exit(0); 
 } 
} 

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您应该在“输入”对话框中只输入数字。parseInt导致异常。添加错误处理，如下所示

        String input = JOptionPane.showInputDialog("Enter number");
        try {
            int number = Integer.parseInt(input);
            int square = number * number;
            System.out.println("square:" + square);
            JOptionPane.showMessageDialog(null, "square:" + square);
        } catch (NumberFormatException exception) {
            JOptionPane.showMessageDialog(null, "Only Numbers are accepted");
        }

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在

输入对话框

中输入数字。它不能包含任何字母或符号字符。