I don't see the claimed problem, it all works as it should 
>> Dancer 1.3202 server 2120 listenin
>> Dancer::Plugin::EscapeHTML (0.22)


http://localhost:3000/?jj={%22name%22:%22jsonFileexample%22,%22problem
+%22:%22thisIsThrProblem\%22withComma%22};oj=jjjj

[download]
{
  jj => "{\"name\":\"jsonFileexample\",\"problem\":\"thisIsThrProblem\\\"withComma\"}",
  oj => "jjjj",
}

use Dancer;
use Data::Dump qw/ pp /;
use Dancer::Plugin::EscapeHTML;
any '/' => sub {
    "<pre>".escape_html( pp( scalar params() ) )."</pre>";;;;
};
dance;

[download]

In reply to Re^2: perl dancer route template hashref pass complex json file to server issue by Anonymous Monk
in thread perl dancer route template hashref pass complex json file to server issue by RamiD

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.