Java简单生成登录图片验证码

我就是我 2023-01-12 14:56 248阅读 0赞

## Java简单生成登录图片验证码 ##

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**用一个类就可以生成验证码，拿去piao！！**

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页面显示代码：

<body>
    <form action="">
        验证码：<input type="text" name="code">
        
        <img src="/imgCode" id="img" alt="验证码" onclick="changeImg()">
    </form>
    </body>
    <script> /*点击图片事件，修改图片路径 随机获得验证码*/ function changeImg() { /*修改图片访问路径 不能一样不然浏览器缓冲机制 发现src没有变化就不去访问服务器*/ document.getElementById("img").src='/imgCode?'+new Date().getTime() } </script>

后台代码：

@WebServlet("/imgCode")
    public class LoginSourceServlet extends HttpServlet { 
        private UserService userService=new UserServiceImpl();
    
        @Override/*生成code验证码*/
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
        	//outputVerifyImage此方法可以获得一个图片验证码，并返回验证码中的验证数值，可以用前台传过来的验证码与之进行比对
        											   //宽度 高度 输出流 几个位数的验证码
            String code = GenerateCode.outputVerifyImage(100, 40, resp.getOutputStream(), 4);
            
            req.getSession().setAttribute("code",code);
        }

> 这里我只用了：GenerateCode 类，可以把它当做一个工具类来使用

显示效果：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW96aHV6aHV5YW5n_size_16_color_FFFFFF_t_70]

工具类代码：（直接粘贴复制即可）

package com.yang.util;
    
    import javax.imageio.ImageIO;
    import java.awt.*;
    import java.awt.geom.AffineTransform;
    import java.awt.image.BufferedImage;
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.util.Arrays;
    import java.util.Random;
    
    public class GenerateCode { 
    
        //使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
        public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
        private static Random random = new Random();
    
        /** * 使用系统默认字符源生成验证码 * * @param verifySize 验证码长度 * @return */
        public static String generateVerifyCode(int verifySize) { 
            return generateVerifyCode(verifySize, VERIFY_CODES);
        }
    
        /** * 使用指定源生成验证码 * * @param verifySize 验证码长度 * @param sources 验证码字符源 * @return */
        public static String generateVerifyCode(int verifySize, String sources) { 
            if (sources == null || sources.length() == 0) { 
                sources = VERIFY_CODES;
            }
            int codesLen = sources.length();
            Random rand = new Random(System.currentTimeMillis());
            StringBuilder verifyCode = new StringBuilder(verifySize);
            for (int i = 0; i < verifySize; i++) { 
                verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
            }
            return verifyCode.toString();
        }
    
        /** * 生成随机验证码文件,并返回验证码值 * * @param w * @param h * @param outputFile * @param verifySize * @return * @throws IOException */
        public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException { 
            String verifyCode = generateVerifyCode(verifySize);
            outputImage(w, h, outputFile, verifyCode);
            return verifyCode;
        }
    
        /** * 输出随机验证码图片流,并返回验证码值 * * @param w * @param h * @param os * @param verifySize * @return * @throws IOException */
        public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException { 
            String verifyCode = generateVerifyCode(verifySize);
            outputImage(w, h, os, verifyCode);
            return verifyCode;
        }
    
        /** * 生成指定验证码图像文件 * * @param w * @param h * @param outputFile * @param code * @throws IOException */
        public static void outputImage(int w, int h, File outputFile, String code) throws IOException { 
            if (outputFile == null) { 
                return;
            }
            File dir = outputFile.getParentFile();
            if (!dir.exists()) { 
                dir.mkdirs();
            }
            try { 
                outputFile.createNewFile();
                FileOutputStream fos = new FileOutputStream(outputFile);
                outputImage(w, h, fos, code);
                fos.close();
            } catch (IOException e) { 
                throw e;
            }
        }
    
        /** * 输出指定验证码图片流 * * @param w * @param h * @param os * @param code * @throws IOException */
        public static void outputImage(int w, int h, OutputStream os, String code) throws IOException { 
            int verifySize = code.length();
            BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            Random rand = new Random();
            Graphics2D g2 = image.createGraphics();
            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            Color[] colors = new Color[5];
            Color[] colorSpaces = new Color[]{ Color.WHITE, Color.CYAN,
                    Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
                    Color.PINK, Color.YELLOW};
            float[] fractions = new float[colors.length];
            for (int i = 0; i < colors.length; i++) { 
                colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
                fractions[i] = rand.nextFloat();
            }
            Arrays.sort(fractions);
    
            g2.setColor(Color.GRAY);// 设置边框色
            g2.fillRect(0, 0, w, h);
    
            Color c = getRandColor(200, 250);
            g2.setColor(c);// 设置背景色
            g2.fillRect(0, 2, w, h - 4);
    
            //绘制干扰线
            Random random = new Random();
            g2.setColor(getRandColor(160, 200));// 设置线条的颜色
            for (int i = 0; i < 20; i++) { 
                int x = random.nextInt(w - 1);
                int y = random.nextInt(h - 1);
                int xl = random.nextInt(6) + 1;
                int yl = random.nextInt(12) + 1;
                g2.drawLine(x, y, x + xl + 40, y + yl + 20);
            }
    
            // 添加噪点
            float yawpRate = 0.05f;// 噪声率
            int area = (int) (yawpRate * w * h);
            for (int i = 0; i < area; i++) { 
                int x = random.nextInt(w);
                int y = random.nextInt(h);
                int rgb = getRandomIntColor();
                image.setRGB(x, y, rgb);
            }
    
            shear(g2, w, h, c);// 使图片扭曲
    
            g2.setColor(getRandColor(100, 160));
            int fontSize = h - 4;
            Font font = new Font("Algerian", Font.ITALIC, fontSize);
            g2.setFont(font);
            char[] chars = code.toCharArray();
            for (int i = 0; i < verifySize; i++) { 
                AffineTransform affine = new AffineTransform();
                affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2);
                g2.setTransform(affine);
                g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
            }
    
            g2.dispose();
            ImageIO.write(image, "png", os);
        }
    
        private static Color getRandColor(int fc, int bc) { 
            if (fc > 255) { 
                fc = 255;
            }
            if (bc > 255) { 
                bc = 255;
            }
            int r = fc + random.nextInt(bc - fc);
            int g = fc + random.nextInt(bc - fc);
            int b = fc + random.nextInt(bc - fc);
            return new Color(r, g, b);
        }
    
        private static int getRandomIntColor() { 
            int[] rgb = getRandomRgb();
            int color = 0;
            for (int c : rgb) { 
                color = color << 8;
                color = color | c;
            }
            return color;
        }
    
        private static int[] getRandomRgb() { 
            int[] rgb = new int[3];
            for (int i = 0; i < 3; i++) { 
                rgb[i] = random.nextInt(255);
            }
            return rgb;
        }
    
        private static void shear(Graphics g, int w1, int h1, Color color) { 
            shearX(g, w1, h1, color);
            shearY(g, w1, h1, color);
        }
    
        private static void shearX(Graphics g, int w1, int h1, Color color) { 
    
            int period = random.nextInt(2);
    
            boolean borderGap = true;
            int frames = 1;
            int phase = random.nextInt(2);
    
            for (int i = 0; i < h1; i++) { 
                double d = (double) (period >> 1)
                        * Math.sin((double) i / (double) period
                        + (6.2831853071795862D * (double) phase)
                        / (double) frames);
                g.copyArea(0, i, w1, 1, (int) d, 0);
                if (borderGap) { 
                    g.setColor(color);
                    g.drawLine((int) d, i, 0, i);
                    g.drawLine((int) d + w1, i, w1, i);
                }
            }
    
        }
    
        private static void shearY(Graphics g, int w1, int h1, Color color) { 
    
            int period = random.nextInt(40) + 10; // 50;
    
            boolean borderGap = true;
            int frames = 20;
            int phase = 7;
            for (int i = 0; i < w1; i++) { 
                double d = (double) (period >> 1)
                        * Math.sin((double) i / (double) period
                        + (6.2831853071795862D * (double) phase)
                        / (double) frames);
                g.copyArea(i, 0, 1, h1, 0, (int) d);
                if (borderGap) { 
                    g.setColor(color);
                    g.drawLine(i, (int) d, i, 0);
                    g.drawLine(i, (int) d + h1, i, h1);
                }
    
            }
        }
    
        public static void main(String[] args) throws IOException { 
            String s = GenerateCode.outputVerifyImage(400, 200, new FileOutputStream("d:/a.jpg"), 4);
            // String s = GenerateCode.generateVerifyCode(5);
            System.out.println(s);
    
        }
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3hpYW96aHV6aHV5YW5n_size_16_color_FFFFFF_t_70]: /images/20221119/2cafd5b965e542088720c434e4c3f843.png