java中生成验证码，以及验证码的使用：
1：验证码生成工具类：
1 import java.awt.Color; 2 import java.awt.Font; 3 import java.awt.Graphics; 4 import java.awt.Graphics2D; 5 import java.awt.RenderingHints; 6 import java.awt.geom.AffineTransform; 7 import java.awt.image.BufferedImage; 8 import java.io.File; 9 import java.io.FileOutputStream; 10 import java.io.IOException; 11 import java.io.OutputStream; 12 import java.util.Arrays; 13 import java.util.Random; 14 15 import javax.imageio.ImageIO; 16 /** 17 * <p><b>VerifyCodeUtils Description:</b> (验证码生成)</p> 18 * <b>DATE:</b> 2016年6月2日 下午3:53:34 19 */ 20 public class VerifyCodeUtils{ 21 22 //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 23 public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ"; 24 private static Random random = new Random(); 25 26 27 /** 28 * 使用系统默认字符源生成验证码 29 * @param verifySize 验证码长度 30 * @return 31 */ 32 public static String generateVerifyCode(int verifySize){ 33 return generateVerifyCode(verifySize, VERIFY_CODES); 34 } 35 /** 36 * 使用指定源生成验证码 37 * @param verifySize 验证码长度 38 * @param sources 验证码字符源 39 * @return 40 */ 41 public static String generateVerifyCode(int verifySize, String sources){ 42 if(sources == null || sources.length() == 0){ 43 sources = VERIFY_CODES; 44 } 45 int codesLen = sources.length(); 46 Random rand = new Random(System.currentTimeMillis()); 47 StringBuilder verifyCode = new StringBuilder(verifySize); 48 for(int i = 0; i < verifySize; i++){ 49 verifyCode.append(sources.charAt(rand.nextInt(codesLen-1))); 50 } 51 return verifyCode.toString(); 52 } 53 54 /** 55 * 生成随机验证码文件,并返回验证码值 56 * @param w 57 * @param h 58 * @param outputFile 59 * @param verifySize 60 * @return 61 * @throws IOException 62 */ 63 public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException{ 64 String verifyCode = generateVerifyCode(verifySize); 65 outputImage(w, h, outputFile, verifyCode); 66 return verifyCode; 67 } 68 69 /** 70 * 输出随机验证码图片流,并返回验证码值 71 * @param w 72 * @param h 73 * @param os 74 * @param verifySize 75 * @return 76 * @throws IOException 77 */ 78 public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException{ 79 String verifyCode = generateVerifyCode(verifySize); 80 outputImage(w, h, os, verifyCode); 81 return verifyCode; 82 } 83 84 /** 85 * 生成指定验证码图像文件 86 * @param w 87 * @param h 88 * @param outputFile 89 * @param code 90 * @throws IOException 91 */ 92 public static void outputImage(int w, int h, File outputFile, String code) throws IOException{ 93 if(outputFile == null){ 94 return; 95 } 96 File dir = outputFile.getParentFile(); 97 if(!dir.exists()){ 98 dir.mkdirs(); 99 } 100 try{ 101 outputFile.createNewFile(); 102 FileOutputStream fos = new FileOutputStream(outputFile); 103 outputImage(w, h, fos, code); 104 fos.close(); 105 } catch(IOException e){ 106 throw e; 107 } 108 } 109 110 /** 111 * 输出指定验证码图片流 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 public static void main(String[] args) throws IOException{ 261 File dir = new File("F:/verifies"); 262 int w = 200, h = 80; 263 for(int i = 0; i < 50; i++){ 264 String verifyCode = generateVerifyCode(4); 265 File file = new File(dir, verifyCode + ".jpg"); 266 outputImage(w, h, file, verifyCode); 267 } 268 } 269 }
2：controller中调用工具类，生成图片：
1 public class AuthImage extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet { 2 static final long serialVersionUID = 1L; 3 4 public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 5 response.setHeader("Pragma", "No-cache"); 6 response.setHeader("Cache-Control", "no-cache"); 7 response.setDateHeader("Expires", 0); 8 response.setContentType("image/jpeg"); 9 10 //生成随机字串 11 String verifyCode = VerifyCodeUtils.generateVerifyCode(4); 12 //存入会话session 13 HttpSession session = request.getSession(true); 14 //删除以前的 15 session.removeAttribute("verCode"); 16 session.setAttribute("verCode", verifyCode.toLowerCase()); 17 //生成图片 18 int w = 100, h = 30; 19 VerifyCodeUtils.outputImage(w, h, response.getOutputStream(), verifyCode); 20 21 } 22 }
3：jsp页面的写法，可更换验证码图片：
1 <!-- 验证码 --> 2 <tr> 3 <td nowrap width="437"></td> 4 <td> 5 <img id="img" src="${ctx}/authImage" /> 6 <a href='#' onclick="javascript:changeImg()" style="color:white;"><label style="color:white;">看不清？</label></a> 7 </td> 8 </tr> 9 10 11 <!-- 触发JS刷新--> 12 <script type="text/javascript"> 13 function changeImg(){ 14 var img = document.getElementById("img"); 15 img.src = "${ctx}/authImage?date=" + new Date();; 16 } 17 </script>