一个简单的验证码生成过程：
1 import javax.imageio.ImageIO; 2 import java.awt.*; 3 import java.awt.geom.AffineTransform; 4 import java.awt.image.BufferedImage; 5 import java.io.File; 6 import java.io.FileOutputStream; 7 import java.io.IOException; 8 import java.io.OutputStream; 9 import java.util.Arrays; 10 import java.util.Random; 11 12 13 public class VerifyCodeUtils { 14 15 //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 16 public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ"; 17 private static Random random = new Random(); 18 19 20 /** 21 * 使用系统默认字符源生成验证码 22 * 23 * @param verifySize 验证码长度 24 * @return 25 */ 26 public static String generateVerifyCode(int verifySize) { 27 return generateVerifyCode(verifySize, VERIFY_CODES); 28 } 29 30 /** 31 * 使用指定源生成验证码 32 * 33 * @param verifySize 验证码长度 34 * @param sources 验证码字符源 35 * @return 36 */ 37 public static String generateVerifyCode(int verifySize, String sources) { 38 if (sources == null || sources.length() == 0) { 39 sources = VERIFY_CODES; 40 } 41 int codesLen = sources.length(); 42 Random rand = new Random(System.currentTimeMillis()); 43 StringBuilder verifyCode = new StringBuilder(verifySize); 44 for (int i = 0; i < verifySize; i++) { 45 verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1))); 46 } 47 return verifyCode.toString(); 48 } 49 50 /** 51 * 生成随机验证码文件,并返回验证码值 52 * 53 * @param w 54 * @param h 55 * @param outputFile 56 * @param verifySize 57 * @return 58 * @throws IOException 59 */ 60 public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException { 61 String verifyCode = generateVerifyCode(verifySize); 62 outputImage(w, h, outputFile, verifyCode); 63 return verifyCode; 64 } 65 66 /** 67 * 输出随机验证码图片流,并返回验证码值 68 * 69 * @param w 70 * @param h 71 * @param os 72 * @param verifySize 73 * @return 74 * @throws IOException 75 */ 76 public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException { 77 String verifyCode = generateVerifyCode(verifySize); 78 outputImage(w, h, os, verifyCode); 79 return verifyCode; 80 } 81 82 /** 83 * 生成指定验证码图像文件 84 * 85 * @param w 86 * @param h 87 * @param outputFile 88 * @param code 89 * @throws IOException 90 */ 91 public static void outputImage(int w, int h, File outputFile, String code) throws IOException { 92 if (outputFile == null) { 93 return; 94 } 95 File dir = outputFile.getParentFile(); 96 if (!dir.exists()) { 97 dir.mkdirs(); 98 } 99 try { 100 outputFile.createNewFile(); 101 FileOutputStream fos = new FileOutputStream(outputFile); 102 outputImage(w, h, fos, code); 103 fos.close(); 104 } catch (IOException e) { 105 throw e; 106 } 107 } 108 109 /** 110 * 输出指定验证码图片流 111 * 112 * @param w 113 * @param h 114 * @param os 115 * @param code 116 * @throws IOException 117 */ 118 public static void outputImage(int w, int h, OutputStream os, String code) throws IOException { 119 int verifySize = code.length(); 120 BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 121 Random rand = new Random(); 122 Graphics2D g2 = image.createGraphics(); 123 g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 124 Color[] colors = new Color[5]; 125 Color[] colorSpaces = new Color[]{Color.WHITE, Color.CYAN, 126 Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE, 127 Color.PINK, Color.YELLOW}; 128 float[] fractions = new float[colors.length]; 129 for (int i = 0; i < colors.length; i++) { 130 colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)]; 131 fractions[i] = rand.nextFloat(); 132 } 133 Arrays.sort(fractions); 134 135 g2.setColor(Color.GRAY);// 设置边框色 136 g2.fillRect(0, 0, w, h); 137 138 Color c = getRandColor(200, 250); 139 g2.setColor(c);// 设置背景色 140 g2.fillRect(0, 2, w, h - 4); 141 142 //绘制干扰线 143 Random random = new Random(); 144 g2.setColor(getRandColor(160, 200));// 设置线条的颜色 145 for (int i = 0; i < 20; i++) { 146 int x = random.nextInt(w - 1); 147 int y = random.nextInt(h - 1); 148 int xl = random.nextInt(6) + 1; 149 int yl = random.nextInt(12) + 1; 150 g2.drawLine(x, y, x + xl + 40, y + yl + 20); 151 } 152 153 // 添加噪点 154 float yawpRate = 0.05f;// 噪声率 155 int area = (int) (yawpRate * w * h); 156 for (int i = 0; i < area; i++) { 157 int x = random.nextInt(w); 158 int y = random.nextInt(h); 159 int rgb = getRandomIntColor(); 160 image.setRGB(x, y, rgb); 161 } 162 163 shear(g2, w, h, c);// 使图片扭曲 164 165 g2.setColor(getRandColor(100, 160)); 166 int fontSize = h - 4; 167 Font font = new Font("Algerian", Font.ITALIC, fontSize); 168 g2.setFont(font); 169 char[] chars = code.toCharArray(); 170 for (int i = 0; i < verifySize; i++) { 171 AffineTransform affine = new AffineTransform(); 172 affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2); 173 g2.setTransform(affine); 174 g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10); 175 } 176 177 g2.dispose(); 178 ImageIO.write(image, "jpg", os); 179 } 180 181 private static Color getRandColor(int fc, int bc) { 182 if (fc > 255) 183 fc = 255; 184 if (bc > 255) 185 bc = 255; 186 int r = fc + random.nextInt(bc - fc); 187 int g = fc + random.nextInt(bc - fc); 188 int b = fc + random.nextInt(bc - fc); 189 return new Color(r, g, b); 190 } 191 192 private static int getRandomIntColor() { 193 int[] rgb = getRandomRgb(); 194 int color = 0; 195 for (int c : rgb) { 196 color = color << 8; 197 color = color | c; 198 } 199 return color; 200 } 201 202 private static int[] getRandomRgb() { 203 int[] rgb = new int[3]; 204 for (int i = 0; i < 3; i++) { 205 rgb[i] = random.nextInt(255); 206 } 207 return rgb; 208 } 209 210 private static void shear(Graphics g, int w1, int h1, Color color) { 211 shearX(g, w1, h1, color); 212 shearY(g, w1, h1, color); 213 } 214 215 private static void shearX(Graphics g, int w1, int h1, Color color) { 216 217 int period = random.nextInt(2); 218 219 boolean borderGap = true; 220 int frames = 1; 221 int phase = random.nextInt(2); 222 223 for (int i = 0; i < h1; i++) { 224 double d = (double) (period >> 1) 225 * Math.sin((double) i / (double) period 226 + (6.2831853071795862D * (double) phase) 227 / (double) frames); 228 g.copyArea(0, i, w1, 1, (int) d, 0); 229 if (borderGap) { 230 g.setColor(color); 231 g.drawLine((int) d, i, 0, i); 232 g.drawLine((int) d + w1, i, w1, i); 233 } 234 } 235 236 } 237 238 private static void shearY(Graphics g, int w1, int h1, Color color) { 239 240 int period = random.nextInt(40) + 10; // 50; 241 242 boolean borderGap = true; 243 int frames = 20; 244 int phase = 7; 245 for (int i = 0; i < w1; i++) { 246 double d = (double) (period >> 1) 247 * Math.sin((double) i / (double) period 248 + (6.2831853071795862D * (double) phase) 249 / (double) frames); 250 g.copyArea(i, 0, 1, h1, 0, (int) d); 251 if (borderGap) { 252 g.setColor(color); 253 g.drawLine(i, (int) d, i, 0); 254 g.drawLine(i, (int) d + h1, i, h1); 255 } 256 257 } 258 259 } 260 261 public static void main(String[] args) throws IOException { 262 File dir = new File("F:/verifies"); 263 int w = 200, h = 80; 264 for (int i = 0; i < 50; i++) { 265 String verifyCode = generateVerifyCode(4); 266 File file = new File(dir, verifyCode + ".jpg"); 267 outputImage(w, h, file, verifyCode); 268 } 269 } 270 }