jquery验证码的事例-six _Web前端

jquery验证码的例子--six
今天研究了jquery验证码的例子，和大家分享一下，也记录自己的点滴进步~~呵呵~~

1、VerifyCodeServlet.java

package verify;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class VerifyCodeServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

// 验证码图片的宽度。
     private int width = 140;

    // 验证码图片的高度。
     private int height = 60;

     // 验证码字符个数
    private int codeCount = 4;

     private int x = 0;

     // 字体高度
     private int fontHeight;

     private int codeY;
     //去掉o和0，i和1
    char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J',
            'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
             'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9' };

     /**
      * 初始化验证图片属性，从web.xml中获得
      */
     public void init() throws ServletException {
        // 宽度
         String sWidth = this.getInitParameter("width");
        // 高度
        String sHeight = this.getInitParameter("height");
         // 字符个数
        String sCodeCount = this.getInitParameter("codeCount");

         //将配置的信息转换成数值
        try {
             if (sWidth != null && sWidth.length() != 0) {
                 width = Integer.parseInt(sWidth);
            }
           if (sHeight != null && sHeight.length() != 0) {
                 height = Integer.parseInt(sHeight);
             }
             if (sCodeCount != null && sCodeCount.length() != 0) {
                 codeCount = Integer.parseInt(sCodeCount);
             }
         } catch (NumberFormatException e) {
        }

        x = width / (codeCount + 1);
         fontHeight = height - 2;
         codeY = height - 4;

     }

     protected void service(HttpServletRequest req, HttpServletResponse resp)
             throws ServletException, java.io.IOException {

         // 定义图像buffer
         BufferedImage buffImg = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
         Graphics2D g = buffImg.createGraphics();

        // 创建一个随机数生成器类
         Random random = new Random();

         // 将图像填充为白色
        g.setColor(Color.WHITE);
         g.fillRect(0, 0, width, height);

        // 创建字体，字体的大小应该根据图片的高度来定。
         Font font = new Font("Fixedsys", Font.PLAIN, fontHeight);
         // 设置字体。
         g.setFont(font);

         // 画边框。
        g.setColor(Color.BLACK);
        g.drawRect(0, 0, width - 1, height - 1);

         // 随机产生180条干扰线，使图象中的认证码不易被其它程序探测到。
         g.setColor(Color.BLACK);
         for (int i = 0; i < 180; 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);
         }

         // randomCode用于保存随机产生的验证码
        StringBuffer randomCode = new StringBuffer();
         int red = 0, green = 0, blue = 0;

         // 随机产生codeCount数字的验证码。字，字母，颜色都是随机分配的
         for (int i = 0; i < codeCount; i++) {
             // 得到随机产生的验证码数字。
             String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
             // 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。
             red = random.nextInt(255);
             green = random.nextInt(255);
             blue = random.nextInt(255);

             // 用随机产生的颜色将验证码绘制到图像中。
             g.setColor(new Color(red, green, blue));
             g.drawString(strRand, (i + 1) * x, codeY);

             // 将产生的四个随机数组合在一起。
             randomCode.append(strRand);
         }
         // 将四位数字的验证码保存到Session中,也可以放到request中
         HttpSession session = req.getSession();
         session.setAttribute("validateCode", randomCode.toString());

         // 禁止图像缓存。
         resp.setHeader("Pragma", "no-cache");
         resp.setHeader("Cache-Control", "no-cache");
         resp.setDateHeader("Expires", 0);

         resp.setContentType("image/jpeg");

         // 将图像输出到Servlet输出流中。
         ServletOutputStream sos = resp.getOutputStream();
         ImageIO.write(buffImg, "jpeg", sos);
         sos.close();
     }

}

2、ResultServlet.java

package verify;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ResultServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {

         doPost(request, response);
     }
     public void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         response.setContentType("text/html;charset=utf-8");
         String validateC = (String) request.getSession().getAttribute("validateCode");
         String veryCode = request.getParameter("cc");
         PrintWriter out = response.getWriter();
         if(veryCode==null||"".equals(veryCode)){
             out.println("验证码为空");
         }else{
             if(validateC.equals(veryCode)){
                 out.println("验证码正确");
             }else{
                 out.println("验证码错误");
             }
         }
         out.flush();
         out.close();
    }

}

3、verifyCode.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
     pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <script type="text/javascript" src="../js/verifyCode.js"></script>
        <script type="text/javascript" src="../js/jquery.js"></script>
        <title>test verify code</title>
        <style type="text/css">
        #infoCode{color:red;font-weight:bold;}
        </style>
    </head>
    <body>
        <input id="veryCode" name="veryCode" type="text"/>
        <img id="imgObj" alt="" src="../verifyCodeServlet"/>
        <a href="#" onclick="changeImg()" >看不清,换一张</a>
        <input type="button" value="验证" onclick="checkVerifyCode()"/>
        <div id="infoCode"></div>
    </body>
</html>

4、verifyCode.js

function changeImg(){
     var imgSrc = $("#imgObj");
     var src = imgSrc.attr("src");
     imgSrc.attr("src",chgUrl(src));
}
//为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳
function chgUrl(url){
      var timestamp = (new Date()).valueOf();
          url = url + "?tamp=" + timestamp;
      return url;
}

function checkVerifyCode(){
      var code = $("#veryCode").attr("value");
      code = "cc=" + code;
      $.ajax({
          type:"POST",
          url:"../ResultServlet",
          data:code,
          success:callback
      });
}

function callback(data){
alert("callback");
      $("#infoCode").html(data);
}

5、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
    <servlet-name>VerifyCodeServlet</servlet-name>
    <servlet-class>verify.VerifyCodeServlet</servlet-class>
</servlet>
<servlet>
    <servlet-name>ResultServlet</servlet-name>
    <servlet-class>verify.ResultServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>VerifyCodeServlet</servlet-name>
    <url-pattern>/verifyCodeServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>ResultServlet</servlet-name>
    <url-pattern>/ResultServlet</url-pattern>
</servlet-mapping>

<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>