获取到一个短连接，需要将短连接转换成真实的网址，通过查资料，发现 PHP 提供了一个函数 get_headers() ，可以完成这个任务，先把 头部信息获取到，然后再分析跳转地址即可：
$url = 'http://t.cn/h5mwx';
$headers = get_headers($url, TRUE);
print_r($headers);
//输出跳转到的网址
echo $headers['Location'];
附完整数组：
Array
(
[0] => HTTP/1.1 302 Moved Temporarily
[Location] => http://www.baidu.com
[Content-Type] => Array
(
[0] => text/html;charset=UTF-8
[1] => text/html;charset=utf-8
)
[Server] => Array
(
[0] => weibo
[1] => BWS/1.0
)
[Content-Length] => Array
(
[0] => 203
[1] => 16424
)
[Date] => Array
(
[0] => Thu, 12 Dec 2013 10:42:25 GMT
[1] => Thu, 12 Dec 2013 10:42:25 GMT
)
[X-Varnish] => 2893360335
[Age] => 0
[Via] => 1.1 varnish
[Connection] => Array
(
[0] => close
[1] => Close
)
)
附：get_headers函数官方文档
get_headers — 取得服务器响应一个 HTTP 请求所发送的所有标头
说明
array get_headers ( string $url [, int $format = 0 ] )
get_headers() 返回一个数组，包含有服务器响应一个 HTTP 请求所发送的标头。
参数
url：目标 URL。
format：如果将可选的 format 参数设为 1，则 get_headers() 会解析相应的信息并设定数组的键名。
返回值
返回包含有服务器响应一个 HTTP 请求所发送标头的索引或关联数组，如果失败则返回 FALSE。
使用例子：
<?php
$url = 'http://www.example.com';
print_r(get_headers($url));
print_r(get_headers($url, 1));
?>
以上例程的输出类似于：
Array
(
[0] => HTTP/1.1 200 OK
[1] => Date: Sat, 29 May 2004 12:28:13 GMT
[2] => Server: Apache/1.3.27 (Unix) (Red-Hat/Linux)
[3] => Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT
[4] => ETag: "3f80f-1b6-3e1cb03b"
[5] => Accept-Ranges: bytes
[6] => Content-Length: 438
[7] => Connection: close
[8] => Content-Type: text/html
)
Array
(
[0] => HTTP/1.1 200 OK
[Date] => Sat, 29 May 2004 12:28:14 GMT
[Server] => Apache/1.3.27 (Unix) (Red-Hat/Linux)
[Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
[ETag] => "3f80f-1b6-3e1cb03b"
[Accept-Ranges] => bytes
[Content-Length] => 438
[Connection] => close
[Content-Type] => text/html
)