指定时间内无序输入账户密码，自动登录

jsp–Cookie控制代码

<% String username = null;
	       String pwd = null;
	       Cookie cookies[] = request.getCookies();
	       if(null != cookies){
		       for(Cookie cookie:cookies){
		           if(cookie.getName().equals("username")){
		               username = cookie.getValue();
		           }
		           if(cookie.getName().equals("pwd")){
		               pwd = cookie.getValue();
		           }
		       } 
	       }
	       if(username != null && pwd!=null){
		       request.getRequestDispatcher("LoginServlet?userName="+username+"&pwd="+pwd).forward(request, response);
	       }
 %>

jsp登录表单

<form action="LoginServlet" method="get">
    用户名：<input type="text"  size="20" name="userName"/><br><br>
    密码 &nbsp;&nbsp;&nbsp;：<input type="password" size="20" name="pwd"/><br/><br/>
    自动登录:<select name="timelength">
			    <option value="0" select>每天都登录</option>
			    <option value="10">10天登录</option>
			    <option value="30">30天登录</option>
		    </select> 
    <br/><br/>
    <div style="margin-left: 2px;">
	    <input type="submit" value="登录" />
	    <INPUT  TYPE="RESET" VALUE="重置" style="margin-left: 30px;" />
    </div> 							
</form>

2、对应的LoginServlet

     int dayLenth = 0;
        if (null != request.getParameter("timelength")) {
            dayLenth = Integer.valueOf(request.getParameter("timelength"));
            Cookie userNameCookie = new Cookie("username",
                request.getParameter("userName"));
            Cookie pwdCookie = new Cookie("pwd",
                    request.getParameter("pwd"));
            userNameCookie.setMaxAge(20);
            pwdCookie.setMaxAge(20);

            response.addCookie(userNameCookie);
            response.addCookie(pwdCookie);
        }
        request.getRequestDispatcher("main.jsp").forward(request, response);

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