perl 解json 中文问题

###列出组信息
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 $token_url= 'http://127.0.0.1:8000/api2/auth-token/';
                
  
   my $res = $ua->post($token_url,
                {
                'username'=>'[email protected]',
                'password'=>'1234567'
                });
   print $res->content();
   print "\n";
   my $r= $res->content();
   my $r=encode_utf