java - 如何处理NumberFormatException : null in Java to cancel and exit the program

Question

我的代码中有这个。整个程序工作正常，除了当您从输入名称对话框中单击“取消”时，它会进入下一个对话框，要求输入回合数。最后退出。它应该在第一个对话框中退出。

有错误的代码:

    String iName = JOptionPane.showInputDialog (null, "Enter name:", JOptionPane.PLAIN_MESSAGE);
    int iRounds = Integer.parseInt(JOptionPane.showInputDialog (null, "Enter number of rounds:", JOptionPane.PLAIN_MESSAGE));

当它应该立即退出时，单击取消会继续执行此操作:

知道如何修复此错误吗？谢谢!

Answer 1

String iName = JOptionPane.showInputDialog (null, "Enter name:", JOptionPane.PLAIN_MESSAGE);

if( ((iName != null) && (iName .length() > 0)) {
    int iRounds = Integer.parseInt(JOptionPane.showInputDialog (null, "Enter number of rounds:", JOptionPane.PLAIN_MESSAGE));
}