登录验证码
public class VerifyCodeServlet extends HttpServlet { ? ????public void doGet(HttpServletRequest request, HttpServletResponse response) ????????????throws ServletException, IOException { ????????/** ???????? * 1.生成图片 ???????? * 2.记录验证码至Session域中 ???????? * 3.发送验证码 ???????? */ ????????VerifyCode vc=new VerifyCode(); ????????BufferedImage bi=vc.getImage(); ???????? ????????request.getSession().setAttribute("session_vcode",vc.getText()); ???????? ????????VerifyCode.output(bi, response.getOutputStream()); ????} ? } |
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LoginServlet
/** ???????? * 1.拿到Session中的验证码 ???????? * 2.拿到浏览器传来的验证码 ???????? * 3.比较 ???????? */ ????????String vcode=(String) request.getSession().getAttribute("session_vcode"); ????????String prame=request.getParameter("verifyCode"); ????????if (!vcode.equalsIgnoreCase(prame)) { ????????????request.setAttribute("message", "验证码不一致"); ????????????request.getRequestDispatcher("anli/login.jsp").forward(request, response); ????????????return; ????????} |
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Login.jsp
????<script type="text/javascript"> ????????function _change(){ ????????????var imgc=document.getElementById("img"); ????????????imgc.src="<%=path%>/VerifyCodeServlet?a="+new Date().getTime(); ????????} ????</script> </head> ? <body> This is my JSP page. <br> <h1>登陆页面</h1> <% String uname=""; Cookie[]cookies=request.getCookies(); ????if(cookies!=null){ ???? for(Cookie c:cookies){ ????if("uname".equals(c.getName())){ ????????uname=c.getValue(); ????} } ????} %> <% String message=""; String mes=(String)request.getAttribute("message"); if(mes!=null){ ????message=mes; } %> <font color="red"><b><%=message %></b></font> <form action="<%=path%>/LoginServlet" method="post"> <!-- 获取cookie中的uname的值放到 用户名文本框中 --> ????用户名：<input type="text" name="username" value="<%= uname%>"><br> ????密 码：<input type="password" name="password"><br> ????验证码：<input type="text" name="verifyCode" size="5"> ????<img id="img" src="<%=path%>/VerifyCodeServlet"><a href="javascript:_change()">换一张</a><br> ????<input type="submit" value="提交"> ???? ? </form> |
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原文：http://www.cnblogs.com/chengzhipcx/p/4995713.html