import javax.swing.JOptionPane;

1 import javax.swing.JOptionPane;
2 public class test2 {
3     public static void main(String[] args) {
4         String result;
5         result=JOptionPane.showInputDialog(null,"你的学号是？");
6   JOptionPane.showMessageDialog(null, "你好，"+result+"!");
7     }
8 }

JOptionPane.showMessageDialog();