Username Availability Check Using Struts2 and AJAX Call [duplicate] - javascript

This question already has an answer here:
How to check for an unique user with jQuery Ajax in Struts 2?
(1 answer)
Closed 6 years ago.
I'm building a web app using Struts2 as a framework. As the title suggest, I'm attempting to check availability of a username using an AJAX call (open to other suggestions if there is something easier that accomplishes the same result.)
Right now I'm having two issues:
Request is null in my doPost function.
Even if I set uname to a string, nothing happens.
Here is what I have for code.
Login.jsp
<s:form action="login.action" method="post" data-parsley-validate="">
<s:textfield name="user.username" key="Username" id="username" onchange="checkUsername()"/><span class="status"></span>
<s:submit method="doTheThing" align="center" onclick="hide()"/>
</s:form>
Javascript
function checkUsername(){
var uname = $(username).val();
if (uname.length > 3) {
$(".status").html("Checking availability...");
$.ajax({
type : "POST",
url : "usernameCheck.action",
data : "uname=" + uname,
success : function(msg) {
$(".status").ajaxComplete(
function(event, request, settings) {
$(".status").html(msg);
});
}
});
}
else {
$(".status").html("username should be at least 3 characters");
}
}
check.java
public class check extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
ActionSupport connectionSupport = new ActionSupport();
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
Connection connection = null;
String URL = "172.ExampleIP";
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(URL, "user","pass");
String uname = request.getParameter("user.username");
PreparedStatement ps = connection.prepareStatement("select username from users where username=?");
ps.setString(1, uname);
ResultSet rs = ps.executeQuery();
if (!rs.next()) {
out.println("<b>" + uname + "</b> is avaliable");
} else {
out.println("<font color=red><b>" + uname + "</b> is already in use</font>");
}
out.println();
} catch (Exception ex) {
out.println("Error ->" + ex.getMessage());
} finally {
out.close();
}
}
public void doGet()
throws ServletException, IOException {
doPost(ServletActionContext.getRequest(), ServletActionContext.getResponse());
}
}
Struts.xml
<action name="usernameCheck" class="java.com.my.package.check" method="doGet"></action>
I'm not sure if this is important information, but the form is on a JQuery modal box.

I found my solution. I changed my java class to extend ActionSupport based on Andrea's suggestion. I changed my struts action result to be of type stream.
<action name="usernameCheck" class="java.com.my.package.check" method="doGet">
<result type="stream">
<param name="contentType">text/html</param>
<param name="inputName">stream</param>
</result>
</action>
I added the following to my java class
private InputStream stream;
public InputStream getStream() {
return stream;
}
And changed my JavaScript success function to the following:
success : function(msg) {
$(".status").html(msg);
}
Thank you all for all the input.

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dataType:"text",
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</td>
</tr>
<tr>
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<td><input type="text" id="txtMessage"/></td>
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<tr>
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</tr>
</table>
</body>
</html>
That is what I have coded till now to get this working. And everything is working finw in FF and Chrome. But in IE it is not working as expected. The request is never gets hold on the server and it always gets executed every second as configured in the javascript code. And it always returns the same result as previous. I have tried to use several other methods to send ajax request for IE but its not working. Can anyone get it working for me?
Since everything works fine in FF and Chrome, I suspect the problem is with javascript code to send the request to get messages.
Please help me.
Thanks in advance.
This is very very frustrating.
To get this thing work properly in IE I need to set cache:false attribute in the ajax request I am creating with jquery for getMessages. Otherwise IE will not hold the request in pending status and always returns back with the old response text.
Its a very big issue with IE. I hope no one face the problem again or finds this answer as early as possible.
:)

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