servlet+jsp 验证码

一、使用JQuery validate插件进行客户端验证

二、在web.xml中配置该Servlet

<servlet><servlet-name>AuthImg</servlet-name><servlet-class>org.agency.servlet.AuthImg</servlet-class></servlet><servlet-mapping><servlet-name>AuthImg</servlet-name><url-pattern>/authImg.jpg</url-pattern></servlet-mapping>

 

三、页面引用

<mce:script type="text/javascript"><!--//验证码function changeImg(){document.getElementById("authImg").src ="authImg.jpg?timpstamp=" + new Date().getTime();}// --></mce:script>验证码:<input type="text" name="code" /><img src="authImg.jpg" mce_src="authImg.jpg" id="authImg" /><input type="button" value="看不清，换一张" onclick="changeImg();" />

 

四、得到验证码！在AuthImg中它把验证码封装到了session对象中名字是rand，然后得到code和session中的rand比较这样验证码的功能就完成了！

AuthImg.javapackage org.agency.servlet;import javax.servlet.*;import javax.servlet.http.*;import java.io.*;import java.awt.*;import java.awt.image.*;import java.util.*;import javax.imageio.*;/** * 图形验证码 hzl 09-11-29 */public class AuthImg extends HttpServlet {private static final long serialVersionUID = 1L;// 定义图形验证码中绘制字符的字体private final Font mFont = new Font("Arial Black", Font.PLAIN, 16);// 定义图形验证码的大小private final int IMG_WIDTH = 100;private final int IMG_HEIGTH = 20;// 定义一个获取随机颜色的方法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);// 得到随机颜色return new Color(r, g, b);}// 重写service方法，生成对客户端的响应public void service(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 设置禁止缓存response.setHeader("Pragma", "No-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);response.setContentType("image/jpeg");BufferedImage image = new BufferedImage(IMG_WIDTH, IMG_HEIGTH,BufferedImage.TYPE_INT_RGB);Graphics g = image.getGraphics();Random random = new Random();g.setColor(getRandColor(200, 250));// 填充背景色g.fillRect(1, 1, IMG_WIDTH - 1, IMG_HEIGTH - 1);// 为图形验证码绘制边框g.setColor(new Color(102, 102, 102));g.drawRect(0, 0, IMG_WIDTH - 1, IMG_HEIGTH - 1);g.setColor(getRandColor(160, 200));// 生成随机干扰线for (int i = 0; i < 80; i++) {int x = random.nextInt(IMG_WIDTH - 1);int y = random.nextInt(IMG_HEIGTH - 1);int xl = random.nextInt(6) + 1;int yl = random.nextInt(12) + 1;g.drawLine(x, y, x + xl, y + yl);}g.setColor(getRandColor(160, 200));// 生成随机干扰线for (int i = 0; i < 80; i++) {int x = random.nextInt(IMG_WIDTH - 1);int y = random.nextInt(IMG_HEIGTH - 1);int xl = random.nextInt(12) + 1;int yl = random.nextInt(6) + 1;g.drawLine(x, y, x - xl, y - yl);}// 设置绘制字符的字体g.setFont(mFont);// 用于保存系统生成的随机字符串String sRand = "";for (int i = 0; i < 6; i++) {String tmp = getRandomChar();sRand += tmp;// 获取随机颜色g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));// 在图片上绘制系统生成的随机字符g.drawString(tmp, 15 * i + 10, 15);}// 获取HttpSesssion对象HttpSession session = request.getSession(true);// 将随机字符串放入HttpSesssion对象中session.setAttribute("rand", sRand);g.dispose();// 向输出流中输出图片ImageIO.write(image, "JPEG", response.getOutputStream());}// 定义获取随机字符串方法private String getRandomChar() {// 生成一个0、1、2的随机数字int rand = (int) Math.round(Math.random() * 2);long itmp = 0;char ctmp = '/u0000';switch (rand) {// 生成大写字母case 1:itmp = Math.round(Math.random() * 25 + 65);ctmp = (char) itmp;return String.valueOf(ctmp);// 生成小写字母case 2:itmp = Math.round(Math.random() * 25 + 97);ctmp = (char) itmp;return String.valueOf(ctmp);// 生成数字default:itmp = Math.round(Math.random() * 9);return itmp + "";}}}