str = "http://img110.sharedimages.org/img.php?id=1334931518<br> http://img108.sharedimages.org/img.php?id=314035875<br>WMV+JPG 1.08GB<br> http://www.jandown.com/link.php?ref=FL0H9XUqL0"
regx = "http://(?:(?!http://).)*<br>";
匹配的最后一个URL出错结果是 http://img108.sharedimages.org/img.php?id=314035875WMV+JPG 1.08GB