验证码

package net.dbet.struts.action;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletOutputStream;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import org.apache.commons.lang.RandomStringUtils;import org.apache.struts.action.Action;import org.apache.struts.action.ActionForm;import org.apache.struts.action.ActionForward;import org.apache.struts.action.ActionMapping;/** * MyEclipse Struts* * XDoclet definition:* @struts.action validate="true"*/public class ImageAction extends Action {/*  * Generated Methods  *//**   * Method execute  * @param mapping  * @param form  * @param request  * @param response  * @return ActionForward  */  public ActionForward execute(ActionMapping mapping, ActionForm form,           HttpServletRequest request, HttpServletResponse response) {         try {           int width = 50;           int height = 18;           // 取得一个4位随机字母数字字符串           String s = RandomStringUtils.random(4, true, true);                      // 保存入session,用于与用户的输入进行比较.           // 注意比较完之后清除session.           HttpSession session = request.getSession(true);           session.setAttribute("validateCode", s);               response.setContentType("images/jpeg");           response.setHeader("Pragma", "No-cache");           response.setHeader("Cache-Control", "no-cache");           response.setDateHeader("Expires", 0);               ServletOutputStream out = response.getOutputStream();           BufferedImage image = new BufferedImage(width, height,               BufferedImage.TYPE_INT_RGB);           Graphics g = image.getGraphics();           // 设定背景色           g.setColor(getRandColor(200, 250));           g.fillRect(0, 0, width, height);               // 设定字体           Font mFont = new Font("Times New Roman", Font.BOLD, 18);// 设置字体           g.setFont(mFont);               // 画边框           // g.setColor(Color.BLACK);           // g.drawRect(0, 0, width - 1, height - 1);               // 随机产生干扰线，使图象中的认证码不易被其它程序探测到           g.setColor(getRandColor(160, 200));           // 生成随机类           Random random = new Random();           for (int i = 0; i < 155; i++) {             int x2 = random.nextInt(width);             int y2 = random.nextInt(height);             int x3 = random.nextInt(12);             int y3 = random.nextInt(12);             g.drawLine(x2, y2, x2 + x3, y2 + y3);           }               // 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)));               g.drawString(s, 2, 16);               // 图象生效           g.dispose();           // 输出图象到页面           ImageIO.write((BufferedImage) image, "JPEG", out);           out.close();         } catch (Exception e) {           e.printStackTrace();         }         return null;       }           private Color getRandColor(int fc, int bc) { // 给定范围获得随机颜色         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);     }   }