How to access a servlet variable inside javascript

Question

I have a servlet which has a variable which holds a JSON string.

JSONObject obj = new JSONObject();
obj.put("parameter", jsonList);
request.setAttribute("jsonstring", obj.toString());
RequestDispatcher rd = request.getRequestDispatcher("/file.jsp");
rd.forward(request, response);

Now I am forwarding my request and response objects to a JSP page which contains a JS file. How can I access the value of jsonstring variable inside the JS file.As I need to parse my JSON string further using jQuery.

I tried doing this in my JS file as I saw in some of the posts online.But it seems like its not working for me.

var test = '<%=request.getAttribute("jsonstring")%>'

Kindly guide me on the same.Thanx.

Anthony Grist · Accepted Answer · 2014-01-30 13:16:51Z

7

If the JSP file uses a <script> tag to load an external JavaScript file, something like this:

<script type="text/javascript" src="js/yourFile.js"></script>

then it won't work. What you have is a JSP scriptlet which only means something during the execution of the JSP file. That yourFile.js file won't be parsed server-side because it doesn't need to be. Only the browser will know what to do with the <script> tag and issue a request to the server to load the JavaScript.

In these cases what you can do is something like this inside your JSP:

<script type="text/javascript">
    var test = <%=request.getAttribute("jsonstring")%>;
</script>
<script type="text/javascript" src="js/yourFile.js"/></script>

Since the JSP scriptlet is inside your JSP file it now actually gets processed correctly, and instead outputs the valid JSON for the object/array to store in the globally scoped test variable, which you can then refer to inside yourFile.js.

answered Jan 30, 2014 at 13:16

Anthony Grist

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3 Comments

guli Over a year ago

You're right, i have missed that he try to do that in a JS file :)

Roger Over a year ago

I'd suggest avoid using scriptlets. Use ${jsonstring} rather

Arpit Over a year ago

@Anthony..I was trying the same with external JS file from hours.Its working now.And thanks for such a nice explanation.:)

guli · Accepted Answer · 2014-01-30 13:10:39Z

1

Try this :

var test = <%=request.getAttribute("jsonstring")%>;

Else try that :

var test = eval('<%=request.getAttribute("jsonstring")%>');

answered Jan 30, 2014 at 13:10

guli

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2 Comments

guli Over a year ago

can you provide the error? And can you provide the value of <%=request.getAttribute("jsonstring")%>?

Arpit Over a year ago

Uncaught SyntaxError: Unexpected token <

Stephen Rauch · Accepted Answer · 2018-07-05 02:21:56Z

1

The solution for me was the following:

<script type="text/javascript">
    var value =<%=request.getAttribute("indicadorId") %>;
</script>

edited Jul 5, 2018 at 2:21

Stephen Rauch♦

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answered Jul 5, 2018 at 2:01

Jorge Santos

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Comments

Sanju2014 · Accepted Answer · 2014-01-30 13:18:05Z

0

put object direct in the request like this

request.setAttribute("jsonstring", obj);

then assign request obj to js variable, it will be accessable as json object;

var test = <%=request.getAttribute("jsonstring")%>;
... = test.parameter;

answered Jan 30, 2014 at 13:18

Sanju2014

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