package com.ghq.controller;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.PrintWriter;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;import javax.servlet.http.HttpSession;public class PicCodeServlet extends HttpServlet{ ???private static final long serialVersionUID = 1L; ???@Override ???public void doGet(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????this.doPost(request, response); ???} ???@Override ???public void doPost(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????request.setCharacterEncoding("utf-8"); ???????????????String method = request.getParameter("whichrequest"); ???????if (method.equals("getCode")) { ???????????getCode(request, response); ???????}else if (method.equals("checkCode")) { ???????????checkCode(request, response); ???????} ???} ???????//验证输入验证码是否正确 ???private void checkCode(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????//获取session中存储的验证码 ???????HttpSession session = request.getSession(); ???????String syscode = (String)session.getAttribute("checkcode"); ???????//获取输入的验证码 ???????String inputcode = request.getParameter("code"); ???????????????response.setContentType("text/html;charset=utf-8"); ???????PrintWriter writer = response.getWriter(); ???????//判断验证码是否相同 ???????if (!syscode.equalsIgnoreCase(inputcode)) { ???????????writer.print("验证码不正确"); ???????} ???????writer.close(); ???} ???????//获取验证码的方法 ???private void getCode(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????Random ran = new Random(); ???????//定义验证码区域的长和宽 ???????int w = 100; ???????int h = 30; ???????//创建图片， bi指向了一个可以访问缓冲区的图片 ???????BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); ???????//获得画笔 ???????Graphics g = bi.getGraphics(); ???????//创建颜色对象 参数范围是[0-255]; ???????Color c = new Color(200+ran.nextInt(50), 200+ran.nextInt(50), 200+ran.nextInt(50)); ???????//存放字体对象 ???????Font f = null; ???????//设置画笔颜色 ???????g.setColor(c); ???????//填充矩形 ???????g.fillRect(0, 0, w, h); ???????//存放验证码的StringBuffer ???????StringBuffer stringbuffer = new StringBuffer(); ???????//在图片上写验证码 ???????for (int i = 0; i < 4; i++) { ???????????c = new Color(100+ran.nextInt(50), 100+ran.nextInt(50), 100+ran.nextInt(50)); ???????????f = new Font("隶书", Font.BOLD, 18); ???????????g.setFont(f); ???????????g.setColor(c); ???????????????????????//产生大小写字母的Unicode码和数字随机数 a为97 ，A为65 ???????????int lowUni = 97+ran.nextInt(26); ???????????int upUni = 65+ran.nextInt(26); ???????????int num = ran.nextInt(10); ???????????//将Unicode码转为字符串 ???????????String lowUnistr = String.valueOf((char)lowUni); ???????????String upUnistr = String.valueOf((char)upUni); ???????????String nstr = String.valueOf(num); ???????????????????????//随机产生大小写字母或数字中的一个 ???????????String checkcode1 = ran.nextInt(2) < 0.5 ? (ran.nextInt(2) < 0.5 ? lowUnistr : upUnistr) : nstr; ???????????stringbuffer.append(checkcode1); ???????????????????????//在图片上写验证码 ???????????g.drawString(checkcode1, (i+1)*20, 20); ???????} ???????//将验证码保存在session中以便进行校验 ???????HttpSession session = request.getSession(); ???????session.setAttribute("checkcode", stringbuffer.toString()); ???????????????//绘制干扰线 ???????for (int i = 0; i < 30; i++) { ???????????c = new Color(150+ran.nextInt(50), 150+ran.nextInt(50), 150+ran.nextInt(50)); ???????????g.setColor(c); ???????????//两点确定一条直线 ???????????int x1 = ran.nextInt(90); ???????????int y1 = ran.nextInt(20); ???????????int x2 = ran.nextInt(20)+x1; ???????????int y2 = ran.nextInt(20)+y1; ???????????g.drawLine(x1, y1, x2, y2); ???????} ???????//将图片绘制到响应的输出流中 ???????ImageIO.write(bi, "jpg", response.getOutputStream()); ???} ???}

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> ?<servlet> ???<servlet-name>PicCodeServlet</servlet-name> ???<servlet-class>com.ghq.controller.PicCodeServlet</servlet-class> ?</servlet> ?<servlet-mapping> ???<servlet-name>PicCodeServlet</servlet-name> ???<url-pattern>/PicCodeServlet</url-pattern> ?</servlet-mapping> ???<welcome-file-list> ???<welcome-file>index.jsp</welcome-file> ?</welcome-file-list></web-app>

　<script type="text/javascript" src="<%=path %>/js/jquery-1.9.1.min.js"></script> ?<script type="text/javascript"> ?function changeCode(){ ?????$("#img").attr("src","<%=path %>/PicCodeServlet?whichrequest=getCode&t="+Math.random()); ?} ?function judgeCode(code){ ?????$.ajax({ ?????????type:"post", ???????url:"<%=path%>/PicCodeServlet", ???????data:"whichrequest=checkCode&code="+code, ???????success:function(resText){ ???????????if (resText == "") { ???????????????$("#spancode").html(resText); ???????????}else{ ???????????????$("#spancode").html(resText); ???????????????changeCode(); ???????????} ???????}, ???????error:function(){ ???????????window.location.href="<%=path%>/building.jsp"; ???????} ?????}); ?} ???function judgename(name){ ?????if (name.trim().length <= 0) { ??????????$("#spanname").html("用户名不能为空"); ????????}else{ ????????????$("#spanname").html(""); ????????} ?} ???function judgepass(pass){ ???????if (pass.trim().length <= 0) { ??????????$("#spanpass").html("密码不能为空"); ????????}else{ ??????????$("#spanpass").html(""); ????????} ?????} ???</script> ?<body> ???<form action="" method="post"> ?????用户名：<input type="text" name="username" onblur="judgename(this.value)"><span id="spanname"></span><br> ?????密码：<input type="password" name="userpass" onblur="judgepass(this.value)"><span id="spanpass"></span><br> ?????验证码：<input type="text" name="checkcode" onblur="judgeCode(this.value)"> ?????<img src="<%=path %>/PicCodeServlet?whichrequest=getCode" onclick="changeCode()" id="img"><span id="spancode"></span> ???</form> ?</body>