php生成uuid

Java代码 
function create_guid() 
{ 
$microTime = microtime(); 
list($a_dec, $a_sec) = explode(" ", $microTime); 
$dec_hex = dechex($a_dec* 1000000); 
$sec_hex = dechex($a_sec); 
ensure_length($dec_hex, 5); 
ensure_length($sec_hex, 6); 
$guid = ""; 
$guid .= $dec_hex; 
$guid .= create_guid_section(3); 
$guid .= '-'; 
$guid .= create_guid_section(4); 
$guid .= '-'; 
$guid .= create_guid_section(4); 
$guid .= '-'; 
$guid .= create_guid_section(4); 
$guid .= '-'; 
$guid .= $sec_hex; 
$guid .= create_guid_section(6); 
return $guid; 
} 
function create_guid_section($characters) 
{ 
$return = ""; 
for($i=0; $i<$characters; $i++) 
{ 
$return .= dechex(mt_rand(0,15)); 
} 
return $return; 
} 
 
function ensure_length(&$string, $length)   
 
{   
    $strlen = strlen($string);   
   if($strlen < $length)   
   {   
        $string = str_pad($string,$length,"0");   
    }   
     else if($strlen > $length)   
   {   
         $string = substr($string, 0, $length);   
  }   
 
 }