<%-- Author: cac Date: 2005-12-30 --%> <%@ page contentType="image/jpeg;charset=UTF-8" %> <%@ page import="javax.imageio.ImageIO,java.awt.*,java.awt.image.BufferedImage,java.util.Random" %> <% System.setProperty("java.awt.headless", "true"); //设置页面不缓存 response.setHeader("Pragma", "No-cache"); response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expires", 0); // 在内存中创建图象 int width = 55, height = 18; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics g = image.getGraphics(); //生成随机类 Random random = new Random(); // 设定背景色 g.setColor(new Color(255, 255, 255)); g.fillRect(0, 0, width, height); //设定字体 g.setFont(new Font("Lucida Console", Font.PLAIN, 14)); // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到 /* g.setColor(getRandColor(160, 200)); for (int i = 0; i < 155; i++) { int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); g.drawLine(x, y, x + xl, y + yl); }*/ // 取随机产生的认证码(4位数字) String sRand = ""; String[] ychar = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C" , "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"}; for (int i = 0; i < 4; i++) { String rand = ychar[random.nextInt(36)]; sRand += rand; // 将认证码显示到图象中 g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110))); //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成 g.drawString(rand, 13 * i + 6, 16); } // 将认证码存入SESSION session.setAttribute("rand", sRand); // 图象生效 g.dispose(); //输出图象到页面 ImageIO.write(image, "JPEG", response.getOutputStream()); out.clear(); out = pageContext.pushBody(); %>