S2SH开发投票管理系统

package sunyang.vote.util; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; @SuppressWarnings("serial") public class SafeCode extends HttpServlet { public SafeCode() { } public void init() throws ServletException { super.init(); } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("image/jpeg"); response.setHeader("Cache-Control", "no-cache"); response.setHeader("Pragma", "No-cache"); response.setDateHeader("Expires", 0L); HttpSession session = request.getSession(); int width = 60; int height = 20; BufferedImage image = new BufferedImage(width, height, 1); Graphics g = image.getGraphics(); Random random = new Random(); g.setColor(getRandColor(200, 250)); g.fillRect(0, 0, width, height); g.setFont(new Font("Arial", 0, 19)); g.setColor(getRandColor(160, 200)); for (int i = 0; i < 155; i++) { int x = random.nextInt(width + 100); int y = random.nextInt(height + 100); int xl = random.nextInt(10); int yl = random.nextInt(12); g.drawOval(x, y, x + xl, y + yl); } String sRand = ""; for (int i = 0; i < 4; i++) { String rand = getRandChar(random.nextInt(36)); sRand = sRand + rand; g.setColor(new Color(20 + random.nextInt(110), 20 + random .nextInt(110), 20 + random.nextInt(110))); g.drawString(rand, 13 * i + 6, 16); } session.setAttribute("rand", sRand); g.dispose(); javax.servlet.ServletOutputStream imageOut = response.getOutputStream(); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(imageOut); encoder.encode(image); } public void destroy() { } private Color getRandColor(int fc, int bc) { Random random = new Random(); if (fc > 255) fc = 255; if (bc > 255) bc = 255; int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b = fc + random.nextInt(bc - fc); return new Color(r, g, b); } private String getRandChar(int randNumber) { return CHARARRAY[randNumber]; } //private static final String CONTENT_TYPE = "image/jpeg"; private static final String CHARARRAY[] = { "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" }; }