我对网络开发非常陌生。
我已经设置的东西
* the Apache server
* DB on Eclipse
* one index.html file with Javascript
* one servlet
目标
* get a credential information
* send via method of 'Javascript -> servlet' to find out user exist.
* from the Javascript method need to receive DB existence.
问题
* I used 'AJAX', looks to me all same as one of Javascript method that does do for asynchronous with HTML and server.
* from the index.html page, if I press wrong information (id, password) then yes it prompts the message.
- 但是如果我输入正确的信息，那么我想要重定向的页面就会出现在上述错误消息页面的区域中。
- 我知道下面的代码是非常菜鸟的构建，但是我是否可以重定向到新页面？
- 请随时纠正我。
Servlet 中的 doPost
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
String name = request.getParameter("user_id");
String password = request.getParameter("passwd");
// search for query user existence
try
{
// TODO session, cookies
sharedConnection = dataSource.getConnection();
Statement stmt = sharedConnection.createStatement();
String str = "select * from customers where email ='" + name + "' and password='" + password + "' ";
ResultSet rs = stmt.executeQuery(str);
HttpSession session = request.getSession();
// not found
if (!rs.next())
{
PrintWriter out = response.getWriter();
out.println("<h3>credentials invalid</h3>");
}
// exist
else
{
String first_name = rs.getString("first_name");
String last_name = rs.getString("last_name");
session.setMaxInactiveInterval(1800); //set timeout to 30min
session.setAttribute("loggedin", true);
session.setAttribute("name", (first_name+ ", " + last_name));
response.sendRedirect("/MovieDB/main.html");
}
}
catch(SQLException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
带有 AJAX 脚本的 HTML
<script type="text/javascript">
function loadXMLDoc()
{
var xmlhttp;
var user_id = document.getElementById('user_id').value;
var passwd = document.getElementById('passwd').value;
<!-- newer browser -->
if (window.XMLHttpRequest)
{
xmlhttp=new XMLHttpRequest();
}
<!-- IE 5, 6 -->
else
{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4)
{
if (xmlhttp.status==200)
document.getElementById("state_msg").innerHTML=xmlhttp.responseText;
}
}
<!-- access servlet with parameters -->
xmlhttp.open("POST", ("LoginServlet?user_id=" + user_id +"&passwd=" + passwd) , true);
xmlhttp.send();
<!-- If Servlet don't detour main.html then we must assume error -->
var err = document.getElementById("state_msg");
err.style.display = "block";
}
</script>
<title>MovieDB : WebAuth</title>
</head>
<body>
<h1>FabFlix WebAuth</h1>
<!-- label user id -->
<div id=input_info>
<label for="user_id">User :</label>
</div>
<!-- user id -->
<input type="text" id="user_id" name="user_id" />
<p></p>
<!-- password label -->
<div id=input_info>
<label for="passwd">Password :</label>
</div>
<!-- password -->
<input type="password" id="passwd" name="passwd" />
<!-- submit button -->
<p></p>
<div id="button_position" align="center">
<button type="button" onclick="loadXMLDoc()">Login</button>
</div>
<div id="state_msg" style="display:none"></div>
</body>
最佳答案
让我们看看它是如何工作的: 您的 xmlhttp 转到 servlet 并等待响应
第一种情况:登录名/密码无效 - 我们收到 HTML 响应 ( <h3>credentials invalid</h3> )
第二种情况:我们也有 HTML 响应! (HTML 页面/MovieDB/main.html)
让代码正常工作的最简单方法就是替换
response.sendRedirect("/MovieDB/main.html");
到
out.println("/MovieDB/main.html");
然后，如果登录名/密码正确，您将获得重定向路径作为响应。现在您可以使用 JavaScript 重定向用户。
关于java - 从 Servlet -> JavaScript 操作登录进度，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5788319/