去除首尾空格：
NSString *content = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
去除首尾空格和换行：
NSString *content = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
原文：http://my.oschina.net/u/1473377/blog/340338