#! /usr/bin/perl
use strict;
use warnings;
use URI;

my $query = 'foo=123&bar=456';

my $uri = URI->new();
$uri->query($query);

my %data = $uri->query_form;
for my $k ( keys %data ) {
    printf "%s : %s\n", $k, $data{$k};
}

__END__