大侠们看一下这段代码，编译通过，运行时只出现空白窗口


import javax.swing.*;
import java.awt.*;public class Registe extends JFrame {
    GridBagLayout grid1;
    JPanel jpRegiste;    JLabel lblUserName;
    JTextField txtUserName;    JLabel lblUserPasswd;
    JPasswordField txtUserPasswd;    JButton btnLogin;
    JButton btnRegiste;    GridBagConstraints gbc;    public Registe() {
//super(title);
        jpRegiste = (JPanel) getContentPane();
        grid1 = new GridBagLayout();
        gbc = new GridBagConstraints();
        jpRegiste.setLayout(grid1);
        ;        lblUserName = new JLabel("用户名：");
        txtUserName = new JTextField(20);
        lblUserPasswd = new JLabel("密　码：");
        txtUserPasswd = new JPasswordField(20);        btnLogin = new JButton("登录");
        btnRegiste = new JButton("注册");        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.gridx = 1;
        gbc.gridy = 5;
        grid1.setConstraints(lblUserName, gbc);
        jpRegiste.add(lblUserName);        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.gridx = 4;
        gbc.gridy = 5;
        grid1.setConstraints(txtUserName, gbc);
        jpRegiste.add(txtUserName);        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.gridx = 1;
        gbc.gridy = 9;
        grid1.setConstraints(lblUserPasswd, gbc);
        jpRegiste.add(lblUserPasswd);        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.gridx = 4;
        gbc.gridy = 9;
        grid1.setConstraints(txtUserPasswd, gbc);
        jpRegiste.add(txtUserPasswd);        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.gridx = 3;
        gbc.gridy = 17;
        grid1.setConstraints(btnLogin, gbc);
        jpRegiste.add(btnLogin);        gbc.anchor = GridBagConstraints.NORTHWEST;
        gbc.gridx = 7;
        gbc.gridy = 17;
        grid1.setConstraints(btnRegiste, gbc);
        jpRegiste.add(btnRegiste);
    }    public static void main(String[] args) {
        Registe registe = new Registe();
        registe.setSize(300, 200);
        registe.setVisible(true);    }
}
主要是你的构造函数前面加了void，这是错误的。