java 彩色验证码实例

package com; import java.awt.*; import java.awt.geom.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; import javax.imageio.ImageIO; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; public class PictureCheckCode extends HttpServlet { public PictureCheckCode() { super(); } public void destroy() { super.destroy(); } public void init() throws ServletException { super.init(); } // 获取随机颜色 public Color getRandColor(int s, int e) { Random random = new Random(); if (s > 255) s = 255; if (e > 255) e = 255; int r = s + random.nextInt(e - s); //随机生成RGB颜色中的r值 int g = s + random.nextInt(e - s); //随机生成RGB颜色中的g值 int b = s + random.nextInt(e - s); //随机生成RGB颜色中的b值 return new Color(r, g, b); } public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setHeader("Pragma", "No-cache"); response.setHeader("Cache-Control", "No-cache"); response.setDateHeader("Expires", 0); // 指定生成的响应是图片 response.setContentType("image/jpeg"); int width = 86; int height = 22; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); Graphics2D g2d = (Graphics2D) g; Random random = new Random(); Font mFont = new Font("黑体", Font.BOLD, 17); g.setColor(getRandColor(200, 250)); g.fillRect(0, 0, width, height); g.setFont(mFont); g.setColor(getRandColor(180, 200)); // 画随机的线条 for (int i = 0; i < 100; i++) { int x = random.nextInt(width - 1); int y = random.nextInt(height - 1); int x1 = random.nextInt(6) + 1; int y1 = random.nextInt(12) + 1; BasicStroke bs = new BasicStroke(2f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL); Line2D line = new Line2D.Double(x, y, x + x1, y + y1); g2d.setStroke(bs); g2d.draw(line); } String sRand = ""; // 输出随机的验证文字 String ctmp = ""; int itmp = 0; for (int i = 0; i < 4; i++) { //random = new Random(new java.util.Date().getTime() + i); switch (random.nextInt(4)) { case 1: itmp = random.nextInt(26) + 65; // 生成A~Z的字母 ctmp = String.valueOf((char) itmp); break; case 2: // 生成汉字 String[] rBase = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" }; // 生成第1位的区码 int r1 = random.nextInt(3) + 11; //生成11到14之间的随机数 String str_r1 = rBase[r1]; // 生成第2位的区码 int r2; if (r1 == 13) { r2 = random.nextInt(7); //生成0到7之间的随机数 } else { r2 = random.nextInt(16); //生成0到16之间的随机数 } String str_r2 = rBase[r2]; // 生成第1位的位码 int r3 = random.nextInt(6) + 10; //生成10到16之间的随机数 String str_r3 = rBase[r3]; // 生成第2位的位码 int r4; if (r3 == 10) { r4 = random.nextInt(15) + 1; //生成1到16之间的随机数 } else if (r3 == 15) { r4 = random.nextInt(15); //生成0到15之间的随机数 } else { r4 = random.nextInt(16); //生成0到16之间的随机数 } String str_r4 = rBase[r4]; System.out.println(str_r1 + str_r2 + str_r3 + str_r4); // 将生成机内码转换为汉字 byte[] bytes = new byte[2]; //将生成的区码保存到字节数组的第1个元素中 String str_r12 = str_r1 + str_r2; int tempLow = Integer.parseInt(str_r12, 16); bytes[0] = (byte) tempLow; //将生成的位码保存到字节数组的第2个元素中 String str_r34 = str_r3 + str_r4; int tempHigh = Integer.parseInt(str_r34, 16); bytes[1] = (byte) tempHigh; ctmp = new String(bytes); //根据字节数组生成汉字 // System.out.println("生成汉字:" + ctmp); break; default: itmp = random.nextInt(10) + 48; // 生成0~9的数字 ctmp = String.valueOf((char) itmp); break; } sRand += ctmp; Color color = new Color(20 + random.nextInt(110), 20 + random .nextInt(110), 20 + random.nextInt(110)); g.setColor(color); /** **随机缩放文字并将文字旋转指定角度* */ // 将文字旋转指定角度 Graphics2D g2d_word = (Graphics2D) g; AffineTransform trans = new AffineTransform(); trans.rotate(random.nextInt(45) * 3.14 / 180, 15 * i + 8, 7); // 缩放文字 float scaleSize = random.nextFloat() +0.8f; if (scaleSize > 1f) scaleSize = 1f; trans.scale(scaleSize, scaleSize); g2d_word.setTransform(trans); /** ********************* */ g.drawString(ctmp, 15 * i + 18, 14); } // 将生成的验证码保存到Session中 HttpSession session = request.getSession(true); session.setAttribute("randCheckCode", sRand); g.dispose(); ImageIO.write(image, "JPEG", response.getOutputStream()); } }