call javascript from servlet in java?

Question

I want to call a function of javascript from servlet.

servlet code:

File ff = new File(uploadedFile+"/"+fileName+".mp4");

FileOutputStream fileOutSt = new FileOutputStream( ff );

fileOutSt.write(data);

fileOutSt.close();

request.setAttribute("src", ff);

RequestDispatcher dispatcher=request.getRequestDispatcher("/WEB-INF/jsfunction.js");
dispatcher.include(request, response);

my javascript code:

myfunction(fileInput)
{
  var fileUrl = window.URL.createObjectURL(fileInput);
}

The problem is javascript calls but it display the code content but not execute it. how can i get fileURL.

Well you are trying to accomplish something wrongly, I suggest you try a different thing. — Darshan Lila
– Darshan Lila, Commented Jul 17, 2015 at 12:20
i dont how to invoke html code from servlet. i just want fileUrl but dont know how to get it. can u help. — monika
– monika, Commented Jul 17, 2015 at 12:24
Well you can put all you html tags along with javascript in it in say a string and can write them to a response using servlets — Darshan Lila
– Darshan Lila, Commented Jul 17, 2015 at 12:27

Little Santi · Accepted Answer · 2015-07-21 09:37:22Z

2

Several things are wrong here:

First, the inclusion of your javascript source is improper, because the javascript must be included (or referenced) always within an HTML file. In your case, instead, you are serving a MP4 file.

If you must absolutely execute that js code (remember that js is always executed in a browser), I suggest you serve an HTML page instead. In this case, the jsfunction.js script must be referenced within the HTML code:

<html>
<head>
<script type="text/javascript" src="jsfunction.js" />
</head>
<body>
...
</body>
</html>

Second: Even if you include the script, you must then invoke your function. You can call it immediately, from a scriptlet, or as a response to some client event (onclick, onload, etc).

edited Jul 21, 2015 at 9:37

answered Jul 17, 2015 at 12:28

Little Santi

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Comments

Suresh Atta · Accepted Answer · 2015-07-17 12:19:10Z

1

javascript plays on client side and Servlet plays on server side. You cannot execute Javascript on serverside. It should execute by browser.

I suggest you to make a javascript call in window onload.

answered Jul 17, 2015 at 12:19

Suresh Atta

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SatyaTNV · Accepted Answer · 2015-07-18 05:17:13Z

0

RequestDispatcher interface provides the facility of dispatching the request to another resource it may be html, servlet or jsp. But not to JS. Since JS always runs in browser itself.

request.setAttribute("filename",filenamehere); //put filename    
RequestDispatcher requestDispatcher; 
requestDispatcher = request.getRequestDispatcher("/filename.jsp");//dispatch here
requestDispatcher.forward(request, response);

In filename.jsp

String value = (String)request.getAttribute("filename");//getting filename

Do like this. This way we will get the file url.

How to pass response from servlet to html

Call your servlet in same html using ajax with jquery.

In servlet

    //getting input from `html` page
    String userName = request.getParameter("userName").trim();
    //now process your request here
    //forward response to `html` page
    response.setContentType("text/plain");
    response.getWriter().write("your file url");

In html call this servlet using ajax

  $.ajax({
        url : 'yourservletaction',
        data : {
            userName : $('#userName').val()//if you want to send any input do like this
        },
        success : function(responseText) {
            $('#ajaxGetUserServletResponse').text(responseText);//getting file url as response. so use this url in you js  
        }
    });

edited Jul 18, 2015 at 5:17

answered Jul 17, 2015 at 12:27

SatyaTNV

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4 Comments

monika Over a year ago

Sir, actually we are using couchDb as document database only. We do not want to store our video in blob format, we just want to convert our video http url to blob http url, just like youtube. i just want to send file object from servelt to javascript. if i am using html then how should i pass the file object. i m really stuck in this problem. plzz help

SatyaTNV Over a year ago

@monika, So you suppose to use jquery with ajax. call your servlet with ajax in your html page. so the response (means file url) this servlet will comes your html page pass this response to your js.

monika Over a year ago

still all the code are showing in the alert as it is. i m simply calling html from dispatcher and execute jsp written in html.. it is nt execute just display in the alert.

SatyaTNV Over a year ago

I Didn't get it. Plz update your code. so that ill see the problem what you are facing.@monika

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