package com.ljdy;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 LoginServlet extends HttpServlet{ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf8"); //request.getSession().setAttribute("name", str); //对name对象赋值 //request.getSession().getAttribute("name") //取得name对象的值 String piccode=(String)request.getSession().getAttribute("piccode"); //获取用户输入的验证码 String checkcode=request.getParameter("checkcode"); //不区分大小写 checkcode=checkcode.toUpperCase(); //创建一个写入对象 PrintWriter out = response.getWriter(); if(checkcode.equals(piccode)){ out.println("验证码输入正确"); }else{ out.println("验证码输入有误，请重新输出"); } out.flush(); out.close(); } }
<%@ 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>My JSP 'index.jsp' starting page</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> <script type="text/javascript"> <%-- function reloadCode(){ document.getElementById("imagecode").src='<%=request.getContextPath()%>/servlet/ImageServlet?ts='+new Date().getTime(); } --%> function reloadCode(){ var time=new Date().getTime(); // ts是请求过去的参数 随便定义 document.getElementById("imagecode").src="<%=request.getContextPath()%>/servlet/ImageServlet?d="+time; }; </script> </head> <body> <div style="text-align: center;"> <form action="<%=request.getContextPath() %>/servlet/LoginServlet" method="get"> 验证码：<input type="text" name="checkcode"/> <img alt="验证码" id="imagecode" src="<%=request.getContextPath() %>/servlet/ImageServlet"/> <a href="javascript: reloadCode();">看不清楚</a><br> <input type="submit" value="提交"> </form></div> </body></html>
package com.ljdy;import java.awt.Color;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class ImageServlet extends HttpServlet{ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //创建图片映像 白纸 BufferedImage bi=new BufferedImage(68, 22, BufferedImage.TYPE_INT_RGB); //获得画笔 Graphics g = bi.getGraphics();// Color color = new Color(200,151,255);//颜色生成// g.setColor(color); g.setColor(Color.gray); //设验证码背景 g.fillRect(0, 0, 68, 22); //toCharArray将字符串转换为字符数组，获得一个含有字母和数字的数组，后续随机从中获取字符 char[] ch="ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789".toCharArray(); Random r=new Random(); int len=ch.length,index; // int len =ch.length;// int index; StringBuffer s=new StringBuffer(); for(int i=0;i<4;i++){ index=r.nextInt(len); // 将产生的随机字母和数字放入index中 g.setColor(new Color(r.nextInt(88),r.nextInt(120),r.nextInt(90))); //给每个验证码创建随机颜色 g.drawString(ch[index]+"", (i)*15+3, 18); //将获得的字符写在图片并设定位置 s.append(ch[index]); //将随机获取的字符放入缓冲区中 保存图片 } request.getSession().setAttribute("newcode",s.toString()); //存至session中，以便后续验证 ImageIO.write(bi, "JPG", response.getOutputStream()); //通过Image输出图片，并传入前台 } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
