十四、PHP下载文件

<?php
header("Content-type:text/html;charset=utf-8");
$file_name="_2017-09-27_18_15.xls";
//用以解决中文不能显示出来的问题
$file_name=iconv("utf-8","gb2312",$file_name);

$file_sub_path=$_SERVER['DOCUMENT_ROOT']."/public/";
$file_path=$file_sub_path.$file_name;
//首先要判断给定的文件存在与否
if(!file_exists($file_path)){
    echo "没有该文件文件";
    return ;
}
$fp=fopen($file_path,"r");
$file_size=filesize($file_path);
//下载文件需要用到的头
Header("Content-type: application/octet-stream");
Header("Accept-Ranges: bytes");
Header("Accept-Length:".$file_size);
Header("Content-Disposition: attachment; filename=".$file_name);
$buffer=1024;
$file_count=0;
//向浏览器返回数据
while(!feof($fp) && $file_count<$file_size){
    $file_con=fread($fp,$buffer);
    $file_count+=$buffer;
    echo $file_con;
}
fclose($fp);

$_SERVER['DOCUMENT_ROOT']