原文:http://www.cnblogs.com/chiangchou/p/VCodeGenerator.html
验证码生成器:
1 package com.lz.Tools; 2 3 import java.awt.Color; 4 import java.awt.Font; 5 import java.awt.Graphics; 6 import java.awt.Graphics2D; 7 import java.awt.image.BufferedImage; 8 import java.util.Random; 9 10 /** 11 * 验证码生成器 12 * 13 * @author bojiangzhou 14 */ 15 public class VCodeGenerator { 16 17 /** 18 * 验证码来源 19 */ 20 final private char[] code = { 21 ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘, 22 ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘, ‘g‘, ‘h‘, ‘i‘, ‘j‘, 23 ‘k‘, ‘m‘, ‘n‘, ‘p‘, ‘q‘, ‘r‘, ‘s‘, ‘t‘, ‘u‘, ‘v‘, 24 ‘w‘, ‘x‘, ‘y‘, ‘z‘, ‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘, 25 ‘G‘, ‘H‘, ‘J‘, ‘K‘, ‘L‘, ‘M‘, ‘N‘, ‘P‘, ‘Q‘, ‘R‘, 26 ‘S‘, ‘T‘, ‘U‘, ‘V‘, ‘W‘, ‘X‘, ‘Y‘, ‘Z‘ 27 }; 28 /** 29 * 字体 30 */ 31 final private String[] fontNames = new String[]{ 32 "黑体", "宋体", "Courier", "Arial", 33 "Verdana", "Times", "Tahoma", "Georgia"}; 34 /** 35 * 字体样式 36 */ 37 final private int[] fontStyles = new int[]{ 38 Font.BOLD, Font.ITALIC|Font.BOLD 39 }; 40 41 /** 42 * 验证码长度 43 * 默认4个字符 44 */ 45 private int vcodeLen = 4; 46 /** 47 * 验证码图片字体大小 48 * 默认17 49 */ 50 private int fontsize = 21; 51 /** 52 * 验证码图片宽度 53 */ 54 private int width = (fontsize+1)*vcodeLen+10; 55 /** 56 * 验证码图片高度 57 */ 58 private int height = fontsize+12; 59 /** 60 * 干扰线条数 61 * 默认3条 62 */ 63 private int disturbline = 3; 64 65 66 public VCodeGenerator(){} 67 68 /** 69 * 指定验证码长度 70 * @param vcodeLen 验证码长度 71 */ 72 public VCodeGenerator(int vcodeLen) { 73 this.vcodeLen = vcodeLen; 74 this.width = (fontsize+1)*vcodeLen+10; 75 } 76 77 /** 78 * 生成验证码图片 79 * @param vcode 要画的验证码 80 * @param drawline 是否画干扰线 81 * @return 82 */ 83 public BufferedImage generatorVCodeImage(String vcode, boolean drawline){ 84 //创建验证码图片 85 BufferedImage vcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 86 Graphics g = vcodeImage.getGraphics(); 87 //填充背景色 88 g.setColor(new Color(246, 240, 250)); 89 g.fillRect(0, 0, width, height); 90 if(drawline){ 91 drawDisturbLine(g); 92 } 93 //用于生成伪随机数 94 Random ran = new Random(); 95 //在图片上画验证码 96 for(int i = 0;i < vcode.length();i++){ 97 //设置字体 98 g.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)], fontsize)); 99 //随机生成颜色 100 g.setColor(getRandomColor()); 101 //画验证码 102 g.drawString(vcode.charAt(i)+"", i*fontsize+10, fontsize+5); 103 } 104 //释放此图形的上下文以及它使用的所有系统资源 105 g.dispose(); 106 107 return vcodeImage; 108 } 109 /** 110 * 获得旋转字体的验证码图片 111 * @param vcode 112 * @param drawline 是否画干扰线 113 * @return 114 */ 115 public BufferedImage generatorRotateVCodeImage(String vcode, boolean drawline){ 116 //创建验证码图片 117 BufferedImage rotateVcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 118 Graphics2D g2d = rotateVcodeImage.createGraphics(); 119 //填充背景色 120 g2d.setColor(new Color(246, 240, 250)); 121 g2d.fillRect(0, 0, width, height); 122 if(drawline){ 123 drawDisturbLine(g2d); 124 } 125 //在图片上画验证码 126 for(int i = 0;i < vcode.length();i++){ 127 BufferedImage rotateImage = getRotateImage(vcode.charAt(i)); 128 g2d.drawImage(rotateImage, null, (int) (this.height * 0.7) * i, 0); 129 } 130 g2d.dispose(); 131 return rotateVcodeImage; 132 } 133 /** 134 * 生成验证码 135 * @return 验证码 136 */ 137 public String generatorVCode(){ 138 int len = code.length; 139 Random ran = new Random(); 140 StringBuffer sb = new StringBuffer(); 141 for(int i = 0;i < vcodeLen;i++){ 142 int index = ran.nextInt(len); 143 sb.append(code[index]); 144 } 145 return sb.toString(); 146 } 147 /** 148 * 为验证码图片画一些干扰线 149 * @param g 150 */ 151 private void drawDisturbLine(Graphics g){ 152 Random ran = new Random(); 153 for(int i = 0;i < disturbline;i++){ 154 int x1 = ran.nextInt(width); 155 int y1 = ran.nextInt(height); 156 int x2 = ran.nextInt(width); 157 int y2 = ran.nextInt(height); 158 g.setColor(getRandomColor()); 159 //画干扰线 160 g.drawLine(x1, y1, x2, y2); 161 } 162 } 163 /** 164 * 获取一张旋转的图片 165 * @param c 要画的字符 166 * @return 167 */ 168 private BufferedImage getRotateImage(char c){ 169 BufferedImage rotateImage = new BufferedImage(height, height, BufferedImage.TYPE_INT_ARGB); 170 Graphics2D g2d = rotateImage.createGraphics(); 171 //设置透明度为0 172 g2d.setColor(new Color(255, 255, 255, 0)); 173 g2d.fillRect(0, 0, height, height); 174 Random ran = new Random(); 175 g2d.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)], fontsize)); 176 g2d.setColor(getRandomColor()); 177 double theta = getTheta(); 178 //旋转图片 179 g2d.rotate(theta, height/2, height/2); 180 g2d.drawString(Character.toString(c), (height-fontsize)/2, fontsize+5); 181 g2d.dispose(); 182 183 return rotateImage; 184 } 185 /** 186 * @return 返回一个随机颜色 187 */ 188 private Color getRandomColor(){ 189 Random ran = new Random(); 190 return new Color(ran.nextInt(220), ran.nextInt(220), ran.nextInt(220)); 191 } 192 /** 193 * @return 角度 194 */ 195 private double getTheta(){ 196 return ((int) (Math.random()*1000) % 2 == 0 ? -1 : 1)*Math.random(); 197 } 198 199 /** 200 * @return 验证码字符个数 201 */ 202 public int getVcodeLen() { 203 return vcodeLen; 204 } 205 /** 206 * 设置验证码字符个数 207 * @param vcodeLen 208 */ 209 public void setVcodeLen(int vcodeLen) { 210 this.width = (fontsize+3)*vcodeLen+10; 211 this.vcodeLen = vcodeLen; 212 } 213 /** 214 * @return 字体大小 215 */ 216 public int getFontsize() { 217 return fontsize; 218 } 219 /** 220 * 设置字体大小 221 * @param fontsize 222 */ 223 public void setFontsize(int fontsize) { 224 this.width = (fontsize+3)*vcodeLen+10; 225 this.height = fontsize+15; 226 this.fontsize = fontsize; 227 } 228 /** 229 * @return 图片宽度 230 */ 231 public int getWidth() { 232 return width; 233 } 234 /** 235 * 设置图片宽度 236 * @param width 237 */ 238 public void setWidth(int width) { 239 this.width = width; 240 } 241 /** 242 * @return 图片高度 243 */ 244 public int getHeight() { 245 return height; 246 } 247 /** 248 * 设置图片高度 249 * @param height 250 */ 251 public void setHeight(int height) { 252 this.height = height; 253 } 254 /** 255 * @return 干扰线条数 256 */ 257 public int getDisturbline() { 258 return disturbline; 259 } 260 /** 261 * 设置干扰线条数 262 * @param disturbline 263 */ 264 public void setDisturbline(int disturbline) { 265 this.disturbline = disturbline; 266 } 267 268 }
在servlet里获取验证码:
1 package com.lz.Servlet; 2 3 import java.awt.image.BufferedImage; 4 import java.io.IOException; 5 6 import javax.imageio.ImageIO; 7 import javax.servlet.ServletException; 8 import javax.servlet.http.HttpServlet; 9 import javax.servlet.http.HttpServletRequest; 10 import javax.servlet.http.HttpServletResponse; 11 12 import com.lz.Tools.VCodeGenerator; 13 14 15 16 /** 17 * 获取验证码 18 * @author bojiangzhou 19 * 20 */ 21 public class GetVCodeServlet extends HttpServlet { 22 23 private static final long serialVersionUID = 3259532010990625726L; 24 25 public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 26 //验证码不能缓存 27 response.setHeader("Expires", "-1"); 28 response.setHeader("cache-control", "no-cahce"); 29 response.setHeader("pragma", "no-cache"); 30 31 VCodeGenerator vcg = new VCodeGenerator(); 32 //取得验证码 33 String vcode = vcg.generatorVCode(); 34 //获取验证码图片 35 // BufferedImage vcodeImage = vcg.generatorRotateVCodeImage(vcode, true); 36 BufferedImage vcodeImage = vcg.generatorVCodeImage(vcode, true); 37 //将验证码保存到session域对象 38 request.getSession().setAttribute("vcode", vcode); 39 //输出验证码图片 40 ImageIO.write(vcodeImage, "gif", response.getOutputStream()); 41 } 42 43 }
前台在img标签里用src获取验证码图片即可
<img class="vcode" src="GetVCodeServlet" />