php实现文件下载实例分享

<?php
class Downfile {

    function downserver($file_name){
$file_path = "./img/".$file_name;
//转码，文件名转为gb2312解决中文乱码
$file_name = iconv("utf-8","gb2312",$file_name);
$file_path = iconv("utf-8","gb2312",$file_path);
$fp = fopen($file_path,"r") or exit("文件不存在");
//定义变量空着每次下载的大小
$buffer = 1024;
//得到文件的大小
$file_size = filesize($file_path);
//header("Content-type:text/html;charset=gb2312");
//会写用到的四条http协议信息
header("Content-type:application/octet-stream");
header("Accept-Ranges:bytes");//可以忽略
header("Content-Length: ".$file_size);//原文这里是Accept-Length经查阅http协议无此项
header("Content-Disposition:attachment;filename=".$file_name);
//字节技术器，纪录当前现在字节数
$count = 0;
while(!feof($fp) && $file_size-$count>0){
//从$fp打开的文件流中每次读取$buffer大小的数据
$file_data = fread($fp,$buffer);
$count+=$buffer;
//将读取到的数据读取出来
echo $file_data;
}
//关闭文件流
fclose($fp);
    }

   }
?>