java - 我试图设置一个仅输入整数的要求，如果输入的其他任何内容都显示错误消息

        ans = JOptionPane.showInputDialog(null,"There are currently "+clubSize+" people inside right now" +
                                                            "\nHow many People are in your party today.");
        int partyIn;
        try
            {
           partyIn = Integer.parseInt(ans);
            }
        catch (NumberFormatException e)
            {
           JOptionPane.showMessageDialog(null, "What you entered was not a number: " + ans);
            }
        if (clubSize + partyIn <= 125)
            {
            clubSize = clubSize + partyIn;
            peopleIn = peopleIn + partyIn;
            }
        else
            {
            JOptionPane.showMessageDialog(null, "Sorry you have to many people in your party");
            }

这又返回错误：变量partyIn可能尚未初始化

最佳答案

使用以下事实：如果输入的数字不是实数，则Integer.parseInt会抛出NumberFormatException。捕获该异常，然后将错误通知用户。

int partyIn;
try
{
   partyIn = Integer.parseInt(ans);
}
catch (NumberFormatException e)
{
   JOptionPane.showMessageDialog(null, "What you entered was not a number: " + ans);
}