String s = new String();
s = textField1.getText();
if s=null
“提示。。”
if (choice1.getSelectedIndex() == 0)
s = s + "先生,";
else
s = s + "女士,";
s = s + "你好!";
textField2.setText(s);
s = textField1.getText();
if s=null
“提示。。”
if (choice1.getSelectedIndex() == 0)
s = s + "先生,";
else
s = s + "女士,";
s = s + "你好!";
textField2.setText(s);
比如说JOptionPane.showMessageDialog(......)
看看这个类的jdk帮助吧