JSP一个正确的验证码
image.jsp页面<%@ page contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="utf-8"%><%!Color getRandColor(int fc,int bc){//给定范围获得随机颜色 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); }%><%//设置页面不缓存response.setHeader("Pragma","No-cache");response.setHeader("Cache-Control","no-cache");response.setDateHeader("Expires", 0);// 在内存中创建图象int width=60, height=20;BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);// 获取图形上下文Graphics g = image.getGraphics();//生成随机类Random random = new Random();// 设定背景色g.setColor(getRandColor(200,250));g.fillRect(0, 0, width, height);//设定字体g.setFont(new Font("Times New Roman",Font.PLAIN,18));//画边框//g.setColor(new Color());//g.drawRect(0,0,width-1,height-1);// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到g.setColor(getRandColor(160,200));for (int i=0;i<155;i++){int x = random.nextInt(width);int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12);g.drawLine(x,y,x+xl,y+yl);}// 取随机产生的认证码(4位数字)//String rand = request.getParameter("rand");//rand = rand.substring(0,rand.indexOf("."));String sRand="";for (int i=0;i<4;i++){ String rand=String.valueOf(random.nextInt(10)); sRand+=rand; // 将认证码显示到图象中 g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成 g.drawString(rand,13*i+6,16);}// 将认证码存入SESSIONsession.setAttribute("rand",sRand);// 图象生效g.dispose();// 输出图象到页面ImageIO.write(image, "JPEG", response.getOutputStream());out.clear();out = pageContext.pushBody();%>
login.jsp页面
<form action="doLogin.jsp" method="post"> 用户名：<input type="text" name="username"/><br> 密码：<input type="password" name="password"/><br>验证码:<input type="text" name="pass"/><img src= "image.jsp "> <br/> <input type="submit" value="提交" /> </form>
doLogin.jsp页面
<%@ page language="java" import="java.util.*,com.wang.entity.*,com.wang.biz.*" pageEncoding="utf-8"%><%request.setCharacterEncoding("utf-8");String username = request.getParameter("username");String password = request.getParameter("password");Users users = new Users(username,password);UsersBiz usersBiz = new UsersBizImpl();Users t_user = usersBiz.CheckUser(users);String pass = request.getParameter("pass");String rand = session.getAttribute("rand").toString();if(!pass.equals(rand)){request.setAttribute("err","验证码错误");request.getRequestDispatcher("login.jsp").forward(request,response);}else if(t_user == null){request.setAttribute("err","用户名错误");request.getRequestDispatcher("login.jsp").forward(request,response);}else if(!t_user.getPassword().equals(password)){request.setAttribute("err","密码错误");request.getRequestDispatcher("login.jsp").forward(request,response);}else{session.setAttribute("user",t_user);response.sendRedirect("/message/listMsg.jsp");}%>
页:
[1]