perl get请求发送json数据

use  LWP::UserAgent;
use LWP;
use Encode;
use LWP::Simple;
use LWP::UserAgent;
use HTTP::Cookies;
use HTTP::Headers;
use HTTP::Response;
use Encode;
use URI::Escape;
use URI::URL;
use JSON;
use Data::Dumper;
  my $ua = LWP::UserAgent->new;
     $ua->agent("Mozilla/5.0 (Windows NT 6.1; rv=>30.0) Gecko/20100101 Firefox/30.0");
  my $cookie_jar = HTTP::Cookies->new(
     file=>'lwp_cookies.txt',
     autosave=>1,
     ignore_discard=>1);
     $ua->cookie_jar($cookie_jar);  
  my    $login_url ="http://2.5.1.55:12731/v2/push";  
  my $timestamp=time();
    my $post=[{"metric"=>"interface.isavailable","endpoint"=>"10.16.36.1","timestamp"=>$timestamp,"step"=>60,"value"=>1,"valuecount"=>1,"counterType"=>"GAUGE","tags"=>{"SYSNAME"=>"CMS","instance"=>"CMS-page-isavailable-1","URL"=>"http=>//100.100.100.100/cms/"}}];
    use JSON qw(encode_json);  
    print '---------------------------'."
";
    $json_string = encode_json($post);  
    print $json_string."
";
    print '---------------------------'."
";
 
    my $req = HTTP::Request->new(  
        'POST' => $login_url
    );  
    $req->content_type('application/json; charset=UTF-8')  
      ;    #post请求,如果有发送参数，必须要有这句  
    $req->content("$json_string");    #发送post的参数  
    my $res = $ua->request($req);
    print '##############################'."
";
    print $res->content();