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Refresh view after response

In one of my #RequestMapping POST methods I need to return HttpServletResponse (which is an xml file) and I want to refresh the view. Normally I would just return path but in this case it gets appended to the xml file which is being downloaded by user.
Is there any way to close and send response first and then generate(refresh) view?

I would say no, it's not. Not a 100 percent sure though. You could try to send the file and also set the redirect header in your response. I didn't try it just now but I guess you will just be redirected. Really depends on the browser though. A browser could decide to still download the file.
Once you sent the response a new request needs to be generated by the client, so there is no way to close it server-side and just create a new one.
I would suggest a solution using Javascript. Either AJAX or just setting the current location twice (first the download, then the new view). I'm not sure, I guess via location.href
Let me know if you need an actual code example, as it would take me some time to manufacture something.

Play-Framework & Ajax how to?

I'm looking to do the following with AJAX...
I have a request to my server that takes a considerable amount of time to complete. The request is made in the controller and upon completion a HTML page is loaded informing the user of its completion.
However, what I'd like to do is have the request sent asynchronously, load the completion page and then load the requests result once it become available. I assume I would use AJAX to do this but I'm not exactly sure how. Can anyone point me to a good guide for doing something like this?
In case my explanation above is too confusing here is what I want to do...
1) Send request to server from Controller asyncronously.
2) load HTML page.
3) When request has completed fill field in already loaded HTML page with the response from the request.

I wrote a tutorial recently that walks through how to do this with Play 1.2, JSON, and jQuery:
Tutorial: Play Framework, JPA, JSON, jQuery, & Heroku

There are 2 parts you need to take into account here:
The client side
The server side
For the client side; an Ajax request (for example, using jQuery.ajax) is per definition asynchronous. This means that you should be able to do the following - again using jQuery, which makes things easier - in your HTML page:
// The ready handler, which fires when the page has been loaded
$(function() {
jQuery.ajax(
// Do your thing here
);
});
For the server side; in case your operation is going to be running for a relatively long time on the server (for instance several web service calls or long running IO operations) you'll want to use Play's asynchronous capabilities to let the Play! server execute things as effeciently as possible. It does this by offloading the long running operation(s) to their own threads.
The only thing left to do is set-up a route to your controller, implement the handler method and render something that your client-side JavaScript code is capable of parsing (JSON is probably the easiest, using Play's renderJson()).
I haven't used this set-up myself - maybe someone can confirm this would be the way to do it?

How to programmatically send a HTTP request with parameters? [duplicate]

This question already has answers here:
How to use java.net.URLConnection to fire and handle HTTP requests
(12 answers)
Closed 7 years ago.
If I use a browser to send information to the server (for example using a log-in, password page), I just fill the user text-box and the password text-box and clicking on the log-in button.
I would like to send this information but without having to use the browser. I would like to 'fill' the text-boxes but without having to do it manually in the browser. May be using a Servlet.
My question is: How to send information in text-boxes, for example, to a website, doing it from a Servlet?

why not just make a call to the URL from Java using a URL like http://your.domain.name/your/servlet/path?userFieldName=THE_VALUE_YOU_WANT_TO_PASS&passwdFieldName=PASSWORD
The servlet will feel like the values are coming from those boxes.
Or you may want to dive into Apache HTTP Client to mimick a request sent from an client.
uh..oh.. are you doing functional testing? Why not look into JMeter?
Updates as per comment
You need to know what actually form submission does? It basically forms a query string composed of Key-Values (KV) pair.
So, if you have a a text field named tfield where user has typed some text, and there is a drop down named, ddfield where user has selected optionX which has value optionX-Val. And this form gets submitted to a URL, http://my.domain.name/my/servlet -- the browser will send a request which will look like
http://my.domain.name/my/servlet?tfield=some%20text&ddfield=optionX-Val
If you want to mimic form submission, you will have to manually create a URL that has a request string containing all the fields and their values as FIELD_NAME=FIELDVALUE ordered pair separated by ampersand (&)
ah, great idea. If you use Firebug (a Firefox extension), open the NET panel in Firebug, make a manual submission of the form that you wanted to mimic. See what request is posted when you submitted the form. It will have exact URL format that you are after. Copy this URL, replace the values and make fake submissions as much as you want.
Hope this helps.

It is not clear to me what you really up to. I assume that the servlet will be the one who will send the data. Here some examples.
Using setAttribute then Forward the request
//On your servlet
request.setAttibute('user', 'admin');
request.setAttribute('password', '123');
getServletContext().getRequestDispatcher("page.jsp").forward(request, response);
//On your jsp page get the value using EL
<span>${user}</span>
Using session
//On your servlet
HttpSession session = request.getSession(true);
session.setAttribute('user', 'admin');
session.setAttribute('password', '123');
getServletContext().getRequestDispatcher("page.jsp").forward(request, response);
//On your jsp page get the value using EL
<span>${user}</span>
The above example is intended to work within the web application. To send information to another web application, which expecting a request. See sample below.
//On your jsp or servlet, you can also do the same within web application
request.sendRedirect('http://example.com?user=admin&password=123');
//on your jsp #example.com
<span>${param.user}</span>
If this is not what you mean, adding more details will be a help.

a servlet takes care of the other end: it's basically a handler for http requests that lives inside a servlet container. If I understand you correctly, you're wanting to send an http request. You can do that using command-line tools like curl, or if you want to stay within java land, you could try this example on exampledepot. Use your favourite search engine to search for more examples, e.g. with search terms such as "sending GET requests through a url".
In your situation, where you need to send information for username and password, you would need to look at the html and find the url for the form element's action attribute. Then you need to find the names of the username and password fields. Using these names as url parameters, you can construct a GET request that mimics sending a form.
NOTE: usually storing a password in plain text in code and/or sending it in plain text to a website is not a good thing to do.

Just in case anyone is interested, there is a plugin for Firefox called Tamper data. With it you can stop the sending of and http request and modify it. It will show you the "url" you need for sending the params, the values they currently have, and their name. You can check it out here. After that you can use a request.sendRedirect('url you got from Tamper Data');

Is it a good practice to use asynchronous requests in this scenario?

I have a scenario that I have a button in JSP page which sends an email, the request is send to servlet asynchronously using jQuery Ajax and JSON, servlet searches in DB, if the user has an email, it returns the email address and sends an email to it, then forwards to the result page with success or fail of sending the email, but in a case that the user doesn't have an email, it returns false values using JSON to JSP and then a JSP form appears to the user to enter his email.
Is it good practice to use Ajax and I know that not each time there's a return value to the user or send request to servlet using get method which return a parameter in a case that the user doesn't have an email?

Using ajax is in practically all cases very good for User Experience. With ajax, the user will experience instant feedback without the need to face an annoying "flash of content" or a (partially) empty page because the whole HTML response needs to be generated/buffered by the server first. This is really a huge plus of using JS/ajax.
Using JSON is generally favorable above XML, HTML or even plain text. But there is no "best practice" with regard to the ajax data exchange format between client and server. Just pick whatever suits the requirement the best. JSON is perfectly fine for this case. jQuery understands it out-the-box and in Java you have choice of a plethora of easy-to-use JSON parsers.
However, when developing an ajax-enabled webapplication, you really need to take into account that the core functionality does not break when the client has JS disabled. This is called Unobtrusive JavaScript. Most of the searchbots, mobile browsers and textbased browsers don't use JS. You should try to use JS only for Progressive Enhancements. To test this yourself, in Firefox you can use for example the Web Developer Toolbar to easily enable/disable JS support. Run your website with JS disabled and observe if the core functionality is maintained as well.
The best way to achieve this is to start developing the website without any single line of JS code, even without a single onclick, onsubmit, onwhatever attribute on the HTML elements. Once you get the core functionality to work, then you can start adding JS in flavor of a script which executes during document ready and attachs functions to the HTML elements of interest (even here, you should not change the original HTML code!). Let the JS functions fire ajax requests on the same URL or maybe a different one, depending on the requirement. You can in the Servlet distinguish between an ajax and normal request as follows:
if ("XMLHttpRequest".equals(request.getHeader("X-Requested-With"))) {
// Handle ajax request. Return JSON response here.
} else {
// Handle normal request. Return normal HTML response here (by JSP).
}
See also:
Simple calculator in JSP - contains unobtrusive JSP/Servlet/jQuery example

Json is just a data-interchange format. Using Json or not has nothing to do with using asynchronous communication or not... You can do both communication types using Json (or XML, or serialized objects, it doesn't matter).
Now, in your problem, it looks like you just want to use Asynchronous communication to improve the user experience (it will not flick the user's browser). If that's the case, Asynchronous communication is the way to go!

I don't think you need ot use AJAX in this.
The main idea of the ajax is to render server response without postback and in your case you are redirecting page after you get some kind of result.
In my opinion you shoul choose on of these two ways.
1) Use AJAX, send data to servlet and then render response from server wether the mail is sent or not.
2) Submit your form to servlet and sent email and then redirect to jsp with the success/fail result.
Hope it helps.

Using ajax to call a servlet

As I understand it and have used it, AJAX is used to make requests from the client to the server and to then update a HTML DIV on the client with new content.
However, I want to use AJAX from a client to a servlet to verify the existence of a URL. If the result is bad, I can set an error message in the servlet and return it to the client page for display.
But does anyone know if, in the case of a positive result, I can have my servlet automatically display another (the next) page to the user? Or should that request be triggered by Javascript on the client when the positive results is received.
Thanks
Mr Morgan.

Since your ajax call is executed in the background the result returned by the servlet, returns to the ajax call, which should then act accordingly to the result. e.g. trigger the display of another page. (Which could have been already in the ajax response and then you can show it in a div or iframe or ...)

As per the W3 specification, XMLHttpRequest forces the webbrowser to the new location when the server returns a fullworthy 301/302 redirect and the Same Origin Policy of the new request is met. This however fails in certain browsers like certain Google Chrome versions.
To achieve best crossbrowser result, also when the redirected URL doesn't met the Same Origin Policy rules, you would like to change the location in JavaScript side instead. You can eventually let your servlet send the status and the desired new URL. E.g.
Map<String, Object> map = new HashMap<String, Object>();
map.put("redirect", true);
map.put("location", "http://stackoverflow.com");
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
resposne.getWriter().write(new Gson().toJson(map));
(that Gson is by the way Google Gson which eases converting Java Objects to JSON)
and then in the Ajax success callback handler in JS:
if (response.redirect) {
window.location = response.location;
}

In your success call back (on client), set the self.location.href to new URL.

HTML is a "pull" technology: Nothing gets displayed in the browser that the browser hasn't previously requested from the server.
Hence, you don't have a chance to "make the servlet automatically display a different page." You have to talk your browser (from JavaScript) into requesting a different page.