将Servlet错误消息重定向到JSP后保存表单数据

小编典典

将Servlet错误消息重定向到JSP后保存表单数据

jsp

我有一个用户登录表单，当密码与数据库中的密码不匹配时会出现一条错误消息。我将错误消息重定向到如下所示的表单，但是当它在表单上显示错误消息时，它将删除电子邮件/密码输入字段中的数据。显示错误消息后如何将数据仍保留在输入字段中？先感谢您。

//将服务重定向到JSP

request.setAttribute("errorMessage", "Wrong credentials!");
                    request.getRequestDispatcher("/Login.jsp").forward(request, response);

// JSP表单页

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<title>User Log in</title>
</head>
<body>
<form action = "LoginServlet" method="POST">
<h3>Sign In</h3><br>

Email: <input type="text" name="email" required><br>
Password: <input type="password" name="pass" required><br>
<div style="color: #FF0000;">${errorMessage}</div><br>
<input type="submit" name="submit" value="Sign in">

</form>
</body>
</html>

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2020-06-10

共1个答案

小编典典

我通过添加以下几行来解决此问题：

// SERVLET

request.setAttribute("email",request.getParameter("email"));
request.setAttribute("pass", request.getParameter("pass"));
request.setAttribute("errorMessage", "Wrong credentials!");
request.getRequestDispatcher("/Login.jsp").forward(request, response);

// JSP页面

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<title>User Log in</title>
<%@ include file="PageHeader.html" %>
</head>
<body>
<form action = "LoginServlet" method="POST">
<h3>Sign In</h3><br>
Email: <input type="text" name="email" required value="${email}"><br>
Password: <input type="password" name="pass" required value="${pass}"><br>
<div style="color: #FF0000;">${errorMessage}</div><br>
<input type="submit" name="submit" value="Sign in" id="sButton">

</form>
</body>
</html>

2020-06-10