下载类软件支持断点续传功能，但在网站建设中如果实现呢？这篇文章主要介绍了PHP实现HTTP断点续传的方法,实例分析了php基于http协议断点续传下载文件的实现方法,需要的朋友可以参考下：

<?php 
/**  
* PHP-HTTP断点续传实现  
* @param string $path: 文件所在路径  
* @param string $file: 文件名  
* @return void  
*/
function download($path,$file) {
   $real = $path.'/'.$file; 
  if(!file_exists($real)) { 
    return false; 
  }  
 $size = filesize($real);  
 $size2 = $size-1;   
$range = 0;  
 if(isset($_SERVER['HTTP_RANGE'])) {
     header('HTTP /1.1 206 Partial Content');
     $range = str_replace('=','-',$_SERVER['HTTP_RANGE']); 
    $range = explode('-',$range); 
    $range = trim($range[1]); 
    header('Content-Length:'.$size);
     header('Content-Range: bytes '.$range.'-'.$size2.'/'.$size);
   } else {
     header('Content-Length:'.$size);
     header('Content-Range: bytes 0-'.$size2.'/'.$size); 
  }  
 header('Accenpt-Ranges: bytes'); 
  header('application/octet-stream'); 
  header("Cache-control: public"); 
  header("Pragma: public");   //解决在IE中下载时中文乱码问题
   $ua = $_SERVER['HTTP_USER_AGENT']; 
  if(preg_match('/MSIE/',$ua)) {
     $ie_filename = str_replace('+','%20',urlencode($file)); 
    header('Content-Dispositon:attachment; 
filename='.$ie_filename); 
  } else {
     header('Content-Dispositon:attachment; filename='.$file); 
  }  
 $fp = fopen($real,'rb+'); 
  fseek($fp,$range); 
  while(!feof($fp)) {  
   set_time_limit(0);  
   print(fread($fp,1024));  
   flush();  
   ob_flush(); 
  }  
 fclose($fp); 
}