以java实现的一个简单登录界面（带验证码）

本文参考与：https://blog.csdn.net/wyf2017/article/details/78831744

https://blog.csdn.net/MengKun822/article/details/89302921

一.登录界面

1.程序代码

 import java.awt.*;//导入awt包
 import javax.swing.*;//导入swing包
 import java.awt.event.ActionListener;//导入awt包中的监听器事件包
 import java.awt.event.ActionEvent;//导入awt包中的ActionEvent事件包

 public class EnterScreen extends JFrame {
     static int s=0;
     public EnterScreen() {
         Yanzhencode vcode = new  Yanzhencode();
         setSize(300,290);//设计窗体的大小
         setTitle("请登录");
         setBackground(Color.RED);//设置背景颜色
         JLabel a=new JLabel("登录名"); //实例化JLabel对象
         JLabel b=new JLabel("密    码");
         JLabel g=new JLabel("忘记用户名/密码？");
         JLabel h=new JLabel("验证码");
         g.setForeground(Color.BLUE);
         JTextField c=new JTextField(15);//实例化用户名文本框
         JPasswordField d=new JPasswordField(15);//实例化密码框
         JTextField k=new JTextField(4);//实例化验证码框
         d.setEchoChar('*');//将输入密码框中的密码以*显示出来
         JButton e=new JButton("登录");
         JButton f=new JButton("快速注册");
         e.setBackground(Color.YELLOW);//设置登录按钮字体颜色
         f.setForeground(Color.GRAY);//设置快速登录按钮填充色
         setVisible(true);//使窗体可视化
         Container m=getContentPane();//获取一个容器
         getContentPane().setBackground(Color.WHITE);//设置窗体填充色
 //        将用户名、密码的Jlabel和用户名JTextField文本框、密码JPasswordField密码框以及确定JButton、快速注册JButton添加到container容器里面                         //
         m.add(a);
         m.add(b);
         m.add(c);
         m.add(d);
         m.add(e);
         m.add(f);
         m.add(g);
         m.add(h);
         m.add(k);
         m.add(vcode);
         setBounds(300,300,300,300);//设置窗体的长宽各为300、300  让其显示在左上方的300、300处
         m.setLayout(null);
 //        a、b、c、d、e、f显示在container容器中的位置坐标
         a.setBounds(10,40,50,18);
         b.setBounds(10,80,50,18);
         c.setBounds(60,40,130,18);
         d.setBounds(60,80,130,18);
         h.setBounds(10,120,50,18);
         k.setBounds(60,120,80,18);
         e.setBounds(90,180,100,30);
         f.setBounds(90,220,100,30);
         g.setBounds(190,75,100,30);
         vcode.setBounds(140,110,80,30);
         e.addActionListener(new ActionListener() {//对登录按钮添加监听事件

             @SuppressWarnings("deprecation")
             @Override
             public void actionPerformed(ActionEvent arg0) {
                 // TODO Auto-generated method stub

                 if(c.getText().trim().equals("xiaoyang")&&new String(d.getPassword()).equals("123456")&&s==1) {//equals函数进行用户名和密码的匹配
                     JOptionPane.showMessageDialog(null,"登录成功");

                     new NewFrame();//进入到NewFrame这个窗体中
                 }else if(c.getText().trim().equals("xiaoyang")&&new String(d.getPassword()).equals("123456")&&s==0) {
                     JOptionPane.showMessageDialog(null,"验证码输入错误");
                 }else {
                     JOptionPane.showMessageDialog(null, "登录失败,用户名、密码或验证码输入错误");
                 }
             }

         });
         f.addActionListener(new ActionListener(){//对快速注册按钮添加监听事件
             @SuppressWarnings("deprecation")
             @Override
             public void actionPerformed(ActionEvent arg0) {
                 // TODO Auto-generated method stub
                 new zhuce();//进入都到zhuce窗体中
             }

         });
         //判断输入验证码是否正确
             if(k.getText()== null) {
                 s=0;
             }else if(vcode.getCode() == null) {
                 s=1;
             }else if(vcode.getCode() .equals(k.getText())) {
                 s=1;
             }else {
             s=0;
         }
     }

         public static void main(String[] args) {
             new EnterScreen();

         }

     }

2.登录界面截图

二.快速注册界面

1.程序代码

 import java.awt.*;
 import javax.swing.*;
 import java.awt.event.ActionListener;
 import java.awt.event.ActionEvent;
 import java.sql.*;
 import java.awt.Container;

 import javax.swing.JButton;
 import javax.swing.JLabel;
 import javax.swing.JPasswordField;
 import javax.swing.JTextField;

 public class zhuce extends JFrame {
     public zhuce() {
         setSize(300,250);//设计窗体的大小
         JLabel a=new JLabel("用户名"); //实例化JLabel对象
         JLabel b=new JLabel("密    码");
         JLabel h=new JLabel("再次确认密码");
         JTextField c=new JTextField(15);//实例化用户名文本框
         JPasswordField d=new JPasswordField(15);//实例化密码文本框
         JPasswordField hd=new JPasswordField(15);//实例化密码文本框
         d.setEchoChar('*');//设置密码隐藏制度
         JButton e=new JButton("确定");
         JButton f=new JButton("重置");
         JButton g=new JButton("返回");
         setVisible(true);
         //获取一个容器
         Container m=getContentPane();
 //        将用户名、密码的Jlabel和用户名JTextField文本框、密码JPasswordField密码框以及确定JButton、快速注册JButton添加到container容器里面
         m.add(a);
         m.add(b);
         m.add(h);
         m.add(hd);
         m.add(c);
         m.add(d);
         m.add(e);
         m.add(f);
         m.add(g);
         //设置窗体的长宽各为300、250  让其显示在左上方的300、250处
         setBounds(300,250,300,250);
         m.setLayout(null);
 //        a、b、c、d、e、f显示在container容器中的位置坐标
         a.setBounds(10,40,50,18);
         b.setBounds(10,80,50,18);
         h.setBounds(5,120,80,18);
         c.setBounds(60,40,200,18);
         d.setBounds(60,80,200,18);
         hd.setBounds(90,120,180,18);
         e.setBounds(110,160,60,30);
         f.setBounds(30,160,60,30);
         g.setBounds(190,160,60,30);
         g.addActionListener(new ActionListener() {//对返回按钮添加监听事件
             @SuppressWarnings("deprecation")
             @Override
             public void actionPerformed(ActionEvent arg0) {
                 // TODO Auto-generated method stub
                 new EnterScreen();

             }
            });
             f.addActionListener(new ActionListener() {//对确认按钮添加监听事件
                 @SuppressWarnings("deprecation")
                 @Override
                 public void actionPerformed(ActionEvent arg0) {
                     // TODO Auto-generated method stub
                     new EnterScreen();

                 }
         });
             e.addActionListener(new ActionListener() {//对确认按钮添加监听事件
                 @SuppressWarnings("deprecation")
                 @Override
                 public void actionPerformed(ActionEvent arg0) {
                     // TODO Auto-generated method stub
                     new zhuce();

                 }
         });
     }
 }

2.快速注册界面截图

三.验证码部分

1.验证码程序

 import java.awt.Color;
     import java.awt.Dimension;
     import java.awt.Font;
     import java.awt.FontMetrics;
     import java.awt.Graphics;
     import java.awt.Graphics2D;
     import java.awt.event.MouseEvent;
     import java.awt.event.MouseListener;  

     import java.util.Random;  

     import javax.swing.JComponent;  

     public class Yanzhencode  extends JComponent implements MouseListener {  

         private String codes;  //自动生成的验证码

         private int width, height = 40;  //设置验证码高度、宽度

         private int codesLength = 4;  //设置代码长度

         private Random random = new Random(); //生成数字的方法 

         public Yanzhencode() {
             width = this.codesLength * 16 + (this.codesLength - 1) * 10; //根据验证码长度设置宽度
             setPreferredSize(new Dimension(width, height));  //设置背景大小
             setSize(width, height);  //设置验证码长度和宽度
             this.addMouseListener(this);
             setToolTipText("点击可更换验证码");
         }
       //得到生成的验证码
         public int getCodesLength() {
             return codesLength;
         }  

         //设置验证码的长度
         public void setCodesLength(int codeLength) {
             if(codesLength < 4) {
                 this.codesLength = 4;
             } else {
                 this.codesLength = codeLength;
             }  

         }  

         public String getCode() {
             return codes;
         }  

            //让验证码产生随机的颜色
         public Color getRandColor(int min, int max) {  

             if (min > 255)
                 min = 255;
             if (max > 255)
                 max = 255;
             int red = random.nextInt(max - min) + min;
             int green = random.nextInt(max - min) + min;
             int blue = random.nextInt(max - min) + min;
             return new Color(red, green, blue);
         }
            // 设置验证码具体的数字或字母是什么
         protected String generateCode() {
             char[] codes = new char[this.codesLength];
             for (int i = 0, len = codes.length; i < len; i++) {
                 if (random.nextBoolean()) {
                     codes[i] = (char) (random.nextInt(10) + 48);
                 } else {
                     codes[i] = (char) (random.nextInt(26) + 97);
                 }
             }
             this.codes = new String(codes);
             return this.codes;
         }  

         @Override
         protected void paintComponent(Graphics g) {
             super.paintComponent(g);
             if(this.codes == null || this.codes.length() != this.codesLength) {  //判断生成的验证码是否为空或超出长度
                 this.codes = generateCode();
             }
             width = this.codesLength * 16 + (this.codesLength - 1) * 10;
             super.setSize(width, height);  //接口使用，验证码字体大小
             super.setPreferredSize(new Dimension(width, height));//接口使用，验证码背景大小
             Font mFont = new Font("Arial", Font.BOLD | Font.ITALIC, 25);  //设置字体和字体大小
             g.setFont(mFont);  //设置对象
             //绘制出验证码的背景的矩形轮廓
             Graphics2D g2d = (Graphics2D) g;
             g2d.setColor(getRandColor(200, 250));
             g2d.fillRect(0, 0, width, height);
             g2d.setColor(getRandColor(180, 200));
             g2d.drawRect(0, 0, width - 1, height - 1);
             //绘制出验证码背景的线
             int i = 0, len = 150;
             for (; i < len; i++) {
                 int x = random.nextInt(width - 1);
                 int y = random.nextInt(height - 1);
                 int x1 = random.nextInt(width - 10) + 10;
                 int y1 = random.nextInt(height - 4) + 4;
                 g2d.setColor(getRandColor(180, 200));
                 g2d.drawLine(x, y, x1, y1);
             }  

             //绘制出验证码的具体字母
             i = 0; len = this.codesLength;
             FontMetrics fm = g2d.getFontMetrics();
             int base = (height - fm.getHeight())/2 + fm.getAscent();
             for(;i<len;i++) {
                 int b = random.nextBoolean() ? 1 : -1;
                 g2d.rotate(random.nextInt(10)*0.01*b);
                 g2d.setColor(getRandColor(20, 130));
                 g2d.drawString(codes.charAt(i)+"", 16 * i + 10, base);
             }
         }  

         //下一个验证码
         public void nextCode() {
             generateCode();
             repaint();
         }  

         @Override
         public void mouseClicked(MouseEvent e) {  

             nextCode();
         }  

         @Override
         public void mousePressed(MouseEvent e) {
             // TODO Auto-generated method stub  

         }  

         @Override
         public void mouseReleased(MouseEvent e) {
             // TODO Auto-generated method stub  

         }  

         @Override
         public void mouseEntered(MouseEvent e) {
             // TODO Auto-generated method stub  

         }  

         @Override
         public void mouseExited(MouseEvent e) {
             // TODO Auto-generated method stub  

         }
     }  

2.验证码实现效果

点击验证码图片后，验证码会更换

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