慕课笔记
servlet制作验证码
ImageServlet类//-------------------------------------------------------------------------------------------------------------
package com.checkcode;
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.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ImageServlet extends HttpServlet{ public void doGet(HttpServletRequest request,HttpServletResponse response){ BufferedImage bi=new BufferedImage(68,22,BufferedImage.TYPE_USHORT_555_RGB); Graphics g=bi.getGraphics(); Color c=new Color(100,188,255); g.setColor(c); g.fillRect(0, 0, 68, 22); char[] ch="ABCDEFGHIJKLMNOPQRSUVWXYZ0123456789FZS".toCharArray(); int length=ch.length; int index; StringBuffer sb=new StringBuffer(); Random r=new Random(); for(int i=0;i<4;++i){ index=r.nextInt(38); g.setColor(new Color(r.nextInt(100),r.nextInt(190),r.nextInt(255))); g.drawString(ch[index]+"", (i*15)+3, 18); sb.append(ch[index]); } request.getSession().setAttribute("checkcode", sb.toString()); try { ImageIO.write(bi, "JPG", response.getOutputStream()); } catch (IOException e) { e.printStackTrace(); } } }
LoginServlet 类
package com.checkcode; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LoginServlet extends HttpServlet { public void doGet(HttpServletRequest request,HttpServletResponse response)throws IOException{ String loginCode=request.getParameter("logincode"); loginCode=loginCode.toUpperCase(); String checkCode=(String) request.getSession().getAttribute("checkcode"); response.setContentType("text/html;charset=utf-8"); PrintWriter out = response.getWriter(); if(checkCode.equals(loginCode)){ out.println("验证码输入正确！"); }else{ out.println("验证码输入不正确！"); } out.flush(); out.close(); } }
web.xml 配置------------------------------------------------------------------------------------------
<?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" 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_3_0.xsd"> <display-name></display-name> <servlet> <servlet-name>ImageServlet</servlet-name> <servlet-class>com.checkcode.ImageServlet</servlet-class> </servlet> <servlet> <servlet-name>LoginServlet</servlet-name> <servlet-class>com.checkcode.LoginServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ImageServlet</servlet-name> <url-pattern>/servlet/ImageServlet</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>LoginServlet</servlet-name> <url-pattern>/servlet/LoginServlet</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
jsp页面-----------------------------------------------------------------------------------
<%@ 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"> --> </head> <script type="text/javascript"> function reloadCode(){ var time=new Date().getTime(); document.getElementById("imagecode").src= "<%=request.getContextPath() %>/servlet/ImageServlet?d="+time; } </script> <body> <form action="<%=request.getContextPath() %>/servlet/LoginServlet" method="get"> 验证码<input type="text" name="logincode"/><br> <img alt="验证码" id="imagecode" src="<%=request.getContextPath() %>/servlet/ImageServlet"/> <a href="javascript:reloadCode();">刷新</a><br> <input type="submit" name="确认" value="确认"/> </form> </body> </html>
web.xml 配置------------------------------------------------------------------------------------------
