3. 用java给一个系统写界面应该怎么写 简单例子可供参考：
import java.awt.*;
import javax.swing.*;
class text2 {
public static void main(String[] args) {
JTextField Name,Number,Class;
JFrame j = new JFrame();
j.setBounds(500, 300, 0, 0);
j.setTitle("Information");
JPanel jp = new JPanel();
jp.setLayout(new GridLayout(4, 1));
final JLabel label_1 = new JLabel();
label_1.setText("Name:");
jp.add(label_1);
Name = new JTextField();
jp.add(Name);
final JLabel label_2 = new JLabel();
label_2.setText("Number:");
jp.add(label_2);
Number = new JTextField();
jp.add(Number);
final JLabel label_3 = new JLabel();
label_3.setText("Class:");
jp.add(label_3);
Class = new JTextField();
jp.add(Class);
final JButton save = new JButton();
jp.add(save);
save.setText（"确认"）；
j.add(jp);
j.pack();
j.setVisible(true);
j.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
4. 用Java怎么写一个简单完整的登陆界面 package com.oristand.cn;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
【java怎么写界面】public class QQlogin extends JFrame{
public QQlogin()
{
JFrame jf= new JFrame("QQ登陆界面")；
jf.setLayout(new GridLayout(5,1,5,5));
JPanel jp=new JPanel();
JLabel jl=new JLabel（"欢迎登陆"）；
jp.add(jl);
jf.add(jp);
JPanel jp1=new JPanel();
JLabel jl1=new JLabel（"用户名"）；
JTextField jt=new JTextField(10);
jp1.add(jl1);
jp1.add(jt);
jf.add(jp1);
JPanel jp2=new JPanel();
JLabel jl2=new JLabel（"密码"）；
JTextField jt1=new JPasswordField(10);
jp2.add(jl2);
jp2.add(jt1);
jf.add(jp2);
JPanel jp3=new JPanel();
JButton jb=new JButton（"登陆"）；
JButton jb1=new JButton（"注册"）；
JButton jb2=new JButton（"设置"）；
jp3.add(jb);
jp3.add(jb1);
jp3.add(jb2);
jf.add(jp3);
JLabel jl3=new JLabel();
jf.add(jl3);
jf.setSize(300,400);
jf.setVisible(true);
jf.setResizable(false);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args)
{
new QQlogin();
}
}
5. java写一个登录界面 import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
class login extends JFrame implements ActionListener
{
public JPasswordField password;
public JTextField name;
JButton ok;
login()
{
setSize(300,200)；//大小
setLocation(200,100);
JPanel panel = new JPanel（)；//创建一个面板对象
panel.setLayout(new GridBagLayout());
Container cn = this.getContentPane();
GridBagConstraints c = new GridBagConstraints();
c.insets = new Insets(5,2,5,5);
c.gridheight = 1;
JLabel user = new JLabel("User:");
c.gridx = 1;
c.gridy = 1;
panel.add(user,c);
name = new JTextField(10);
c.gridx = 2;
panel.add(name,c);
JLabel pass = new JLabel("assword:");
c.gridx = 1;
c.gridy = 2;
panel.add(pass,c);
password = new JPasswordField(10);
c.gridx = 2;
c.gridy = 2;
panel.add(password,c);
c.gridx = 1;
c.gridy = 3;
ok = new JButton("login");
ok.addActionListener(this);
panel.add(ok,c);
cn.add(panel);
}
public void actionPerformed(ActionEvent e)
{
Object source = e.getSource();
if(source == ok)
{