最近要做一个网站,要求实现验证码程序,经过不断调试,终于成功实现功能。
一、验证码生成类
生成验证码的话需要用到java的Graphics类库,画出一个验证码
废话不多说,直接上代码
二、验证码验证类
package verificationCode;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;@WebServlet("/checkCode")public class checkCode extends HttpServlet { private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String code = request.getParameter("code"); response.setCharacterEncoding("utf-8");//保证格式正确 response.setContentType("text/html"); // 验证验证码 String sessionCode = request.getSession().getAttribute("code").toString(); if (code != null && !"".equals(code) && sessionCode != null && !"".equals(sessionCode)) { if (code.equalsIgnoreCase(sessionCode)) { response.getWriter().println("验证通过!"); } else { response.getWriter().println("验证失败!"); } } else { response.getWriter().println("验证失败!"); } }}三、验证码传输类
用到doget方法
package verificationCode;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.awt.image.RenderedImage;import java.io.IOException;import java.util.HashMap;import java.util.Map;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import verificationCode.generateCode;/** * Servlet implementation class CodeServlet */@WebServlet("/getCode")public class CodeServlet extends HttpServlet { private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // 调用工具类生成的验证码和验证码图片 Map<String, Object> codeMap = generateCode.generateCodeAndPic(); // 将四位数字的验证码保存到Session中。 HttpSession session = req.getSession(); session.setAttribute("code", codeMap.get("code").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; try { sos = resp.getOutputStream(); ImageIO.write((RenderedImage) codeMap.get("codePic"), "jpeg", sos); sos.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } }}四、jsp验证demo
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>验证码页面</title><script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery.js"></script></head><body> <form action="${pageContext.request.contextPath}/checkCode" method="post"> 请输入验证码:<input type="text" name="code" style="width: 80px;" /> <div id=random> <img id="imgObj" alt="验证码" src="${pageContext.request.contextPath}/getCode"> </div><button id="b01" type="button">改变内容</button><br/> <input type="submit" value="提交" /> </form></body><script type="text/javascript"> $(function() { //response.getWriter().println("验证失败!"); }); $("#b01").click( function changeImg() { $("#random").html("<img id='imgObj' alt='验证码' src='${pageContext.request.contextPath}/getCode'>") var imgSrc = $("#imgObj"); var src = imgSrc.attr("src"); imgSrc.attr("src", chgUrl(src)); }); // 时间戳 // 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.substring(0, 20); if ((url.indexOf("&") >= 0)) { url = url + "×tamp=" + timestamp; } else { url = url + "?timestamp=" + timestamp; } return url; }</script></html>总结
虽然只是一个小小的demo,但是实际上用到了许多知识,比如生成验证码的画图,传输验证码doget,验证验证码的dopost和ajax动态更换验证码,麻雀虽小五脏俱全啊。
参考网址: Java实现验证码的产生和验证
更多关于java验证码的精彩文章请点击专题: java验证码大全 进行参考
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