Response/Request between Javascript/Java Servlet

Question

I have a simple test client-server app. Client is html/javascript, server - Java Servlet

First of all I want to test request/response mechanism. Therefore I have used a simple code for cliet(jQuery):

$.get ("http://localhost:8081/TestProject/BasicServlet",
       function(data) {
          alert('Data:' +data);
       }
);

And on the server side:

protected void doGet(HttpServletRequest req, HttpServletResponse res) ... {
      String callBack = "TestCallback";
      res.setContentType("text/html");
      ServletOutputStream out = res.getOutputStream();
      out.write(callBack.getBytes("UTF-8"));
      out.flush();
}

So, Servlet catches request from client, but I have a problem with response, response header looks good, with character attributes, but I don't receive the callBack data

As response in Firebug I have 3 tabs, Header, Answer, HTML. Answer and HTML are empty

EDIT: I have found a Problem: it was Access-Control-Allow-Origin violation. Thanks for help !

Your JavaScript looks invalid (is that a function call? Where are the ()? How do you expect an object with no values for any of its keys to work?), and I've no idea what $ is. Prototype.js? Mootools? — Quentin
– Quentin, Commented May 3, 2011 at 15:50
Check to see in firebug if "TestCallback" is in the response. — Karthik Ramachandran
– Karthik Ramachandran, Commented May 3, 2011 at 15:50
That's was a typo in my post, because I post from another computer and my code is on the other one — Le_Coeur
– Le_Coeur, Commented May 3, 2011 at 16:00

Aravindan R · Accepted Answer · 2011-05-03 19:41:39Z

1

As per the documentation in here

http://download.oracle.com/javaee/6/api/javax/servlet/ServletResponse.html#getOutputStream

is used for sending binary data. So my guess is that Content-Type header is set as some MIME type which is not recognized by jQuery. I suggest you check whether the Content-Type header is still "text/html" in the response using FireBug, or use

PrintWriter writer = res.getWriter();
writer.write(callBack);
writer.flush();

By the way, for sending textual data using PrintWriter is the recommended approach.

edited May 3, 2011 at 19:41

answered May 3, 2011 at 16:13

Aravindan R

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1 Comment

Bozho Over a year ago

I don't think the text/plain is a requirement.

Karthik · Accepted Answer · 2011-05-04 11:58:24Z

0

Try out.print() instead of out .write() you will get the response in your ajax call.

answered May 4, 2011 at 11:58

Karthik

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