java图形化界面实现登录窗口

//模拟qq登录窗口
import java.awt.*;
import java.io.*;
import java.awt.event.*;
import javax.swing.*;

public class QQGUI extends JFrame implements ActionListener{
 private JLabel userLa;
 private JLabel pwdLa;
 private JLabel verCodeLa;//验证码
 private JTextField userTxt;
 private JPasswordField pwdTxt;
 private JTextField verCodeTxt;//验证码
 private JButton sureBt;
 private JButton quitBt;
 private Mypanel mp;

 //构造方法
 public QQGUI()
 {
  Init();
 }
 public void Init()
 {
  Frame frame = new Frame("QQ登录");

  //创建出控件对象（因为上面只是声明出来，并没有给出实际的空间)

  //用户文本
  userLa = new JLabel();
  userLa.setText("用户名：");
  userLa.setSize(60, 50);
  userLa.setLocation(100, 80);

  //密码文本
  pwdLa = new JLabel();
  pwdLa.setText("密码：");
  pwdLa.setSize(50, 50);
  pwdLa.setLocation(100, 120);

  //用户输入框
  userTxt = new JTextField();
  userTxt.setSize(100, 20);
  //this.setSize(width, height)
  userTxt.setLocation(170, 95);

  //密码输入框
  pwdTxt = new JPasswordField();
  pwdTxt.setSize(100, 20);
  pwdTxt.setLocation(170, 135);

  //确认按钮
  sureBt = new JButton("登录");
  sureBt.setSize(60, 25);
  sureBt.setLocation(135, 260);

  //退出按钮
  quitBt = new JButton("退出");
  quitBt.setSize(60, 25);
  quitBt.setLocation(240, 260);

  //验证码文本
  verCodeLa = new JLabel();
  verCodeLa.setText("验证码：");
  verCodeLa.setSize(60, 50);
  verCodeLa.setLocation(100,165);

  //验证码文本框
  verCodeTxt = new JTextField();
  verCodeTxt.setSize(100, 20);
  verCodeTxt.setLocation(170, 180);

  //验证码
  mp = new Mypanel();
  mp.setSize(100, 30);
  mp.setLocation(280, 175);

  //登录方式选择框
  JComboBox xlk=new JComboBox();
  xlk.setSize(60, 20);
  xlk.setLocation(250, 220);
  xlk.addItem("在线");
  xlk.addItem("隐身");
  xlk.addItem("离开");


  this.setLayout(null);
  this.setSize(500, 400);
  this.add(userLa);
  this.add(pwdLa);
  this.add(userTxt);
  this.add(pwdTxt);
  this.add(sureBt);
  this.add(quitBt);
  this.add(verCodeLa);
  this.add(verCodeTxt);
  this.add(mp);
  this.add(xlk);
  sureBt.addActionListener(this);
  quitBt.addActionListener(this);
  this.setVisible(true);
 }
 //具体事件的处理
  public void actionPerformed(ActionEvent e)
  {
   //获取产生事件的事件源强制转换
   JButton bt = (JButton)e.getSource();
   //获取按钮上显示的文本
   String str = bt.getText();
   if(str.equals("登录"))
   {
    if(!CheckIsNull())
    {
     //获取用户所输入的用户名
     String user = userTxt.getText().trim();
     //获取用户所输入的密码
     String pwd = pwdTxt.getText().trim();
     if(checkUserAndPwd(user,pwd))
     {

      //隐藏当前登录窗口
      this.setVisible(false);
      //验证成功创建一个主窗口
      MainFrame frame = new MainFrame();
     }
     else
     {
      //如果错误则弹出一个显示框
      JOptionPane pane = new JOptionPane("用户或密码错误");
      JDialog dialog = pane.createDialog(this,"警告");
      dialog.show();
     }
    }
   }
   else
   {
    //调用系统类中的一个正常退出
    System.exit(0);
   }
  }
  private boolean CheckIsNull()
  {
   boolean flag = false;
   if(userTxt.getText().trim().equals(" "))
   {
    flag = true;
   }
   else
   {
    if(pwdTxt.getText().trim().equals(" "))
    {
     flag = true;
    }
   }
   return flag;
  }
  private boolean checkUserAndPwd(String user,String pwd)
  {
   boolean result = false;
   try
   {
    FileReader file = new FileReader("D:\\Workspaces\\MyEclipse 8.5\\testGUI.txt"); 
    BufferedReader bre = new BufferedReader(file);
    String str = bre.readLine();

   while(str!=null)
   {
     String[] strs = str.split(",");
     if(strs[0].equals(user))
     {
      if(strs[1].equals(pwd))
      result = true;
     }
     str = bre.readLine();
   }
   file.close();
   }catch(Exception ex)
   {
    System.out.print("");
   }
   return result;
  }
}

//MainFrame类
import javax.swing.*;
public class MainFrame extends JFrame {
 public MainFrame()
 {
  this.setSize(300, 300);
  this.setVisible(true);
 }
}

//验证码的生成
import java.awt.*;
import java.util.*;
public class Mypanel extends Panel {
 public void paint(Graphics g)
 {
  int height = 50;
  int width = 90;
  //验证码框背景颜色
  g.setColor(Color.LIGHT_GRAY);
  //填充验证码背景
  g.fillRect(0, 0, width, height);
  g.setColor(Color.BLACK);
  g.drawRect(0, 0, width-1, height-1);
  Random r = new Random();
  //设置干扰点
  for(int i = 0;i<100;i++)
  {
   int x = r.nextInt(width)-1;
   int y = r.nextInt(height)-1;
   g.drawOval(x, y, 2, 2);
  }
  g.setFont(new Font("黑体",Font.BOLD,20));//设置验证码字体以及大小
  g.setColor(Color.RED);//设置验证码字体颜色
  //生成随机验证码
  char[] tmp = ("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
  StringBuilder sb = new StringBuilder();
  for(int i = 0;i<4;i++)
  {
   int pos = r.nextInt(tmp.length);
   char c = tmp[pos];
   sb.append(c + " ");
  }
  g.drawString(sb.toString(), 10, 15);//写入验证码
 }
}

//下拉框的实现
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class xialakuang extends JFrame {
 private JComboBox comboBox;//定义一个组合框
 public void xia ()
 {

  //JPanel panel = new JPanel();//创建一个JPanel面板
  comboBox = new JComboBox();
  comboBox.addItem("在线");
  comboBox.addItem("隐身");
  comboBox.addItem("离开");

  this.add(comboBox);
  //this.add(panel);
  this.setSize(200, 100);
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  this.setVisible(true);
 }
}

//测试
public class testQQGUI {

 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  QQGUI frame = new QQGUI();
 }
}