Java简单生成登录图片验证码

我就是我 2023-01-12 14:56 275阅读 0赞

Java简单生成登录图片验证码

用一个类就可以生成验证码，拿去piao！！

页面显示代码：

  1. <body>
  2. <form action="">
  3.     验证码：<input type="text" name="code">
  4.     <!--src会自动请求访问服务器 获得 验证码资源-->
  5.     <img src="/imgCode" id="img" alt="验证码" onclick="changeImg()">
  6. </form>
  7. </body>
  8. <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：

  1. @WebServlet("/imgCode")
  2. public class LoginSourceServlet extends HttpServlet { 
  3.     private UserService userService=new UserServiceImpl();
  5.     @Override/*生成code验证码*/
  6.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
  7.         //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
  8.                                                    //宽度 高度 输出流 几个位数的验证码
  9.         String code = GenerateCode.outputVerifyImage(100, 40, resp.getOutputStream(), 4);
  11.         req.getSession().setAttribute("code",code);
  12.     }

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

工具类代码：（直接粘贴复制即可）

  1. package com.yang.util;
  3. import javax.imageio.ImageIO;
  4. import java.awt.*;
  5. import java.awt.geom.AffineTransform;
  6. import java.awt.image.BufferedImage;
  7. import java.io.File;
  8. import java.io.FileOutputStream;
  9. import java.io.IOException;
  10. import java.io.OutputStream;
  11. import java.util.Arrays;
  12. import java.util.Random;
  14. public class GenerateCode { 
  16.     //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
  17.     public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
  18.     private static Random random = new Random();
  20.     /** * 使用系统默认字符源生成验证码 * * @param verifySize 验证码长度 * @return */
  21.     public static String generateVerifyCode(int verifySize) { 
  22.         return generateVerifyCode(verifySize, VERIFY_CODES);
  23.     }
  25.     /** * 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 */
  26.     public static String generateVerifyCode(int verifySize, String sources) { 
  27.         if (sources == null || sources.length() == 0) { 
  28.             sources = VERIFY_CODES;
  29.         }
  30.         int codesLen = sources.length();
  31.         Random rand = new Random(System.currentTimeMillis());
  32.         StringBuilder verifyCode = new StringBuilder(verifySize);
  33.         for (int i = 0; i < verifySize; i++) { 
  34.             verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
  35.         }
  36.         return verifyCode.toString();
  37.     }
  39.     /** * 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 */
  40.     public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException { 
  41.         String verifyCode = generateVerifyCode(verifySize);
  42.         outputImage(w, h, outputFile, verifyCode);
  43.         return verifyCode;
  44.     }
  46.     /** * 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 */
  47.     public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException { 
  48.         String verifyCode = generateVerifyCode(verifySize);
  49.         outputImage(w, h, os, verifyCode);
  50.         return verifyCode;
  51.     }
  53.     /** * 生成指定验证码图像文件 * * @param w * @param h * @param outputFile * @param code * @throws IOException */
  54.     public static void outputImage(int w, int h, File outputFile, String code) throws IOException { 
  55.         if (outputFile == null) { 
  56.             return;
  57.         }
  58.         File dir = outputFile.getParentFile();
  59.         if (!dir.exists()) { 
  60.             dir.mkdirs();
  61.         }
  62.         try { 
  63.             outputFile.createNewFile();
  64.             FileOutputStream fos = new FileOutputStream(outputFile);
  65.             outputImage(w, h, fos, code);
  66.             fos.close();
  67.         } catch (IOException e) { 
  68.             throw e;
  69.         }
  70.     }
  72.     /** * 输出指定验证码图片流 * * @param w * @param h * @param os * @param code * @throws IOException */
  73.     public static void outputImage(int w, int h, OutputStream os, String code) throws IOException { 
  74.         int verifySize = code.length();
  75.         BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
  76.         Random rand = new Random();
  77.         Graphics2D g2 = image.createGraphics();
  78.         g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  79.         Color[] colors = new Color[5];
  80.         Color[] colorSpaces = new Color[]{ Color.WHITE, Color.CYAN,
  81.                 Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
  82.                 Color.PINK, Color.YELLOW};
  83.         float[] fractions = new float[colors.length];
  84.         for (int i = 0; i < colors.length; i++) { 
  85.             colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
  86.             fractions[i] = rand.nextFloat();
  87.         }
  88.         Arrays.sort(fractions);
  90.         g2.setColor(Color.GRAY);// 设置边框色
  91.         g2.fillRect(0, 0, w, h);
  93.         Color c = getRandColor(200, 250);
  94.         g2.setColor(c);// 设置背景色
  95.         g2.fillRect(0, 2, w, h - 4);
  97.         //绘制干扰线
  98.         Random random = new Random();
  99.         g2.setColor(getRandColor(160, 200));// 设置线条的颜色
  100.         for (int i = 0; i < 20; i++) { 
  101.             int x = random.nextInt(w - 1);
  102.             int y = random.nextInt(h - 1);
  103.             int xl = random.nextInt(6) + 1;
  104.             int yl = random.nextInt(12) + 1;
  105.             g2.drawLine(x, y, x + xl + 40, y + yl + 20);
  106.         }
  108.         // 添加噪点
  109.         float yawpRate = 0.05f;// 噪声率
  110.         int area = (int) (yawpRate * w * h);
  111.         for (int i = 0; i < area; i++) { 
  112.             int x = random.nextInt(w);
  113.             int y = random.nextInt(h);
  114.             int rgb = getRandomIntColor();
  115.             image.setRGB(x, y, rgb);
  116.         }
  118.         shear(g2, w, h, c);// 使图片扭曲
  120.         g2.setColor(getRandColor(100, 160));
  121.         int fontSize = h - 4;
  122.         Font font = new Font("Algerian", Font.ITALIC, fontSize);
  123.         g2.setFont(font);
  124.         char[] chars = code.toCharArray();
  125.         for (int i = 0; i < verifySize; i++) { 
  126.             AffineTransform affine = new AffineTransform();
  127.             affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2);
  128.             g2.setTransform(affine);
  129.             g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
  130.         }
  132.         g2.dispose();
  133.         ImageIO.write(image, "png", os);
  134.     }
  136.     private static Color getRandColor(int fc, int bc) { 
  137.         if (fc > 255) { 
  138.             fc = 255;
  139.         }
  140.         if (bc > 255) { 
  141.             bc = 255;
  142.         }
  143.         int r = fc + random.nextInt(bc - fc);
  144.         int g = fc + random.nextInt(bc - fc);
  145.         int b = fc + random.nextInt(bc - fc);
  146.         return new Color(r, g, b);
  147.     }
  149.     private static int getRandomIntColor() { 
  150.         int[] rgb = getRandomRgb();
  151.         int color = 0;
  152.         for (int c : rgb) { 
  153.             color = color << 8;
  154.             color = color | c;
  155.         }
  156.         return color;
  157.     }
  159.     private static int[] getRandomRgb() { 
  160.         int[] rgb = new int[3];
  161.         for (int i = 0; i < 3; i++) { 
  162.             rgb[i] = random.nextInt(255);
  163.         }
  164.         return rgb;
  165.     }
  167.     private static void shear(Graphics g, int w1, int h1, Color color) { 
  168.         shearX(g, w1, h1, color);
  169.         shearY(g, w1, h1, color);
  170.     }
  172.     private static void shearX(Graphics g, int w1, int h1, Color color) { 
  174.         int period = random.nextInt(2);
  176.         boolean borderGap = true;
  177.         int frames = 1;
  178.         int phase = random.nextInt(2);
  180.         for (int i = 0; i < h1; i++) { 
  181.             double d = (double) (period >> 1)
  182.                     * Math.sin((double) i / (double) period
  183.                     + (6.2831853071795862D * (double) phase)
  184.                     / (double) frames);
  185.             g.copyArea(0, i, w1, 1, (int) d, 0);
  186.             if (borderGap) { 
  187.                 g.setColor(color);
  188.                 g.drawLine((int) d, i, 0, i);
  189.                 g.drawLine((int) d + w1, i, w1, i);
  190.             }
  191.         }
  193.     }
  195.     private static void shearY(Graphics g, int w1, int h1, Color color) { 
  197.         int period = random.nextInt(40) + 10; // 50;
  199.         boolean borderGap = true;
  200.         int frames = 20;
  201.         int phase = 7;
  202.         for (int i = 0; i < w1; i++) { 
  203.             double d = (double) (period >> 1)
  204.                     * Math.sin((double) i / (double) period
  205.                     + (6.2831853071795862D * (double) phase)
  206.                     / (double) frames);
  207.             g.copyArea(i, 0, 1, h1, 0, (int) d);
  208.             if (borderGap) { 
  209.                 g.setColor(color);
  210.                 g.drawLine(i, (int) d, i, 0);
  211.                 g.drawLine(i, (int) d + h1, i, h1);
  212.             }
  214.         }
  215.     }
  217.     public static void main(String[] args) throws IOException { 
  218.         String s = GenerateCode.outputVerifyImage(400, 200, new FileOutputStream("d:/a.jpg"), 4);
  219.         // String s = GenerateCode.generateVerifyCode(5);
  220.         System.out.println(s);
  222.     }
  223. }

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