#!/usr/bin/env perl                                                                                               

use JSON::XS;
use Data::Dumper;

my %hash = ( cl_ip => 209890 );

my $json = encode_json \%hash;

print Dumper( \%hash );

print qq($json\n);

$hash{ cl_ip } += 0;

$json = encode_json \%hash;

print Dumper( \%hash );

print qq($json\n);

__END__

karl-mac-mini:monks karl$ ./json.pl                                                                               
    $VAR1 = {                                                                                                     
          'cl_ip' => 209890                                                                                       
};                                                                                                                
{"cl_ip":209890}                                                                                                  
$VAR1 = {                                                                                                         
          'cl_ip' => 209890                                                                                       
        };                                                                                                        
{"cl_ip":209890}