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jsp中生成的验证码和存在session里面的验证码不一致的处理

2014-05-23 18:41 405 查看
摘要: 最近做项目遇到的问题。下面直接附上我的例子：截图如下：代码如下：1.JAVA类：CodeServlet.java:[java] view plaincopypackage cn.gov.csrc.servlet;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 com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;public class CodeServlet extends HttpServlet {/*** 产生验证码图片*/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);int width = 80;int height = 30;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, 25));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 code = request.getParameter("code");String sRand = code;for (int i = 0; i < sRand.length(); i++) {String rand = sRand.substring(i, i + 1);g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));g.drawString(rand, 14 * i + 5, 25);}g.dispose();javax.servlet.ServletOutputStream imageOut = response.getOutputStream();JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(imageOut);encoder.encode(image);}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);}}
2.Web.xml文件：[html] view plaincopy<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name></display-name><welcome-file-list><welcome-file>index.jsp</welcome-file></welcome-file-list><servlet><servlet-name>CodeServlet</servlet-name><servlet-class>cn.gov.csrc.servlet.CodeServlet</servlet-class></servlet><servlet-mapping><servlet-name>CodeServlet</servlet-name><url-pattern>/CodeServlet</url-pattern></servlet-mapping></web-app>3.index.jsp：[javascript] view plaincopy<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme() + "://"+ request.getServerName() + ":" + request.getServerPort()+ path + "/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><base href="<%=basePath%>"><title>验证码测试</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"><meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><script language="javascript" type="text/javascript">var code ; //在全局 定义验证码function createCode(){code = "";var codeLength = 5;//验证码的长度//所有候选组成验证码的字符，可以用中文var selectChar = new Array(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','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(var i=0;i<codeLength;i++){var charIndex = Math.floor(Math.random()*60);code +=selectChar[charIndex];}return code;}function validate (){var inputCode = document.getElementById("vcode").value.toLowerCase();if(inputCode.length <=0){alert("请输入验证码！");return false;}else if(inputCode != code.toLowerCase()){alert("验证码输入错误！");show();//刷新验证码return false;}else{alert("^-^ OK");return true;}}function show(){//显示验证码document.getElementById("code").src="CodeServlet?code="+createCode();}window.onload = function() {//document.onload=show();show();//页面加载时加载验证码//这时无论在ie还是在firefox中，js没有加载完，页面的东西是不会被执行的；}</script></head><body><form onsubmit="return validate();" action="" method="post"><h3>jsp+js+servlet实现验证码</h3><br /> 用户名：<input type="text" name="" /><br /> 请输入验证码： <inputtype="text" id="vcode" style="width: 60;" maxLength="5" /> <imgsrc="" id="code" /> <a href="#" mce_href="#"onclick="javascript:show();return false;">看不清,换一张!</a><br /> <inputtype="submit" /></form></body></html>
                                            

                                        

                        
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                         标签： 
                                                session
                                                jsp
                                                验证码
                                                

                        

                    


                

            


            

                
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