JavaWeb-登入的驗證與自動跳轉到登入頁面
阿新 • • 發佈：2018-10-31
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%-- 本行程式碼可以防止亂碼出現 --%> <% 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>Task04-login</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"> </head> <body> <!--傳值到"login_action.jsp" 方式是post隱式傳遞。--> <form action="/FridayJob/Task/Task04/login_action.jsp" method="post"> <!-- 通過正則表示式決定輸入的字元 --> 使用者名稱:<input pattern="[a-zA-Z0-9]{6,12}" name="username">(只能由字母數字組成，長度在6-12位之間)<br /> 密碼:<input pattern="[a-zA-Z0-9]{6,12}" type="password" name="password">(只能由字母數字組成，長度在6-15位之間)<br /> <input type="submit" value="登入"><br> </form> </body> </html>
<%@ page language="java" contentType="text/html; charset=UTF-8" 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>Task04-login_action</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"> </head> <body> <% String username = request.getParameter("username"); String password = request.getParameter("password"); %> <!-- 判斷字串是否為空,為空就轉到最初的登入頁面 --> <% if (username.equals("") && password.equals("")) { response.setHeader("refresh", "3;URL=/FridayJob/Task/Task04/login.jsp");//這裡的3,是你要確定的時間秒 URL是要跳轉的地址 %><font color="red" size="5"> 您的登入資訊為空<br> 三秒後將跳轉到登入頁面 <br> 如果沒有跳轉,請點選 <a href="/FridayJob/Task/Task04/login.jsp">這裡</a>!!! <br> </font> <% } else { out.print("使用者名稱:" + username); %><br> <% out.print("密碼:" + password); %><br> <% if (username != null) { if (username.equals("sweety") && password.equals("123456")) { out.print("welcome!!!"); } else { response.setHeader("refresh", "3;URL=/FridayJob/Task/Task04/login.jsp"); %><font color="red" size="5"> 您的登入資訊有誤<br> 三秒後將跳轉到登入頁面 <br> 如果沒有跳轉,請點選 <a href="/FridayJob/Task/Task04/login.jsp">這裡</a>!!! <br> </font> <% } } } %> </body> </html>
輸入內容為空的話,會自動跳轉的
錯誤的話,也會自動跳轉到登入頁面
成功
