php实现大文件断点续传下载实例，看完你就知道超过100M以上的大文件如何断点传输了，这个功能还是比较经典实用的，毕竟大文件上传功能经常用得到。

require_once('download.class.php'); date_default_timezone_set('Asia/Shanghai'); error_reporting(E_STRICT); function errorHandler($errno, $errstr, $errfile, $errline) {  echo '<p>error:', $errstr, '</p>';  exit(); } set_error_handler('errorHandler'); define('IS_DEBUG', true); $filePath = 'test.zip'; $mimeType = 'audio/x-matroska'; $range = isset($_SERVER['HTTP_RANGE']) ? $_SERVER['HTTP_RANGE'] : null; if (IS_DEBUG) { // $range = "bytes=1000-1999\n2000"; // $range = "bytes=1000-1999,2000"; // $range = "bytes=1000-1999,-2000"; // $range = "bytes=1000-1999,2000-2999"; } set_time_limit(0); $transfer = new Transfer($filePath, $mimeType, $range); if (IS_DEBUG) {  $transfer->setIsLog(true); } $transfer->send();

download.class.php

/**  * 文件传输，支持断点续传。  * 2g以上超大文件也有效  * @author MoXie  */ class Transfer {  /**   * 缓冲单元   */  const BUFF_SIZE = 5120; // 1024 * 5  /**   * 文件地址   * @var <String>   */  private $filePath;  /**   * 文件大小   * @var <String> Php超大数字 字符串形式描述   */  private $fileSize;  /**   * 文件类型   * @var <String>   */  private $mimeType;  /**   * 请求区域（范围）   * @var <String>   */  private $range;  /**   * 是否写入日志   * @var <Boolean>   */  private $isLog = false;  /**   *   * @param <String> $filePath 文件路径   * @param <String> $mimeType 文件类型   * @param <String> $range 请求区域（范围）   */  function __construct($filePath, $mimeType = null, $range = null) {   $this->filePath = $filePath;   $this->fileSize = sprintf('%u', filesize($filePath));   $this->mimeType = ($mimeType != null) ? $mimeType : "application/octet-stream"; // bin   $this->range = trim($range);  }  /**   * 获取文件区域   * @return <Map> {'start':long,'end':long} or null   */  private function getRange() {   /**    * Range: bytes=-128    * Range: bytes=-128    * Range: bytes=28-175,382-399,510-541,644-744,977-980    * Range: bytes=28-175\n380    * type 1    * RANGE: bytes=1000-9999    * RANGE: bytes=2000-9999    * type 2    * RANGE: bytes=1000-1999    * RANGE: bytes=2000-2999    * RANGE: bytes=3000-3999    */   if (!empty($this->range)) {    $range = preg_replace('/[\s|,].*/', '', $this->range);    $range = explode('-', substr($range, 6));    if (count($range) < 2) {     $range[1] = $this->fileSize; // Range: bytes=-100    }    $range = array_combine(array('start', 'end'), $range);    if (empty($range['start'])) {     $range['start'] = 0;    }    if (!isset($range['end']) || empty($range['end'])) {     $range['end'] = $this->fileSize;    }    return $range;   }   return null;  }  /**   * 向客户端发送文件   */  public function send() {   $fileHande = fopen($this->filePath, 'rb');   if ($fileHande) {    // setting    ob_end_clean(); // clean cache    ob_start();    ini_set('output_buffering', 'Off');    ini_set('zlib.output_compression', 'Off');    $magicQuotes = get_magic_quotes_gpc(); //   set_magic_quotes_runtime(0);    // init    $lastModified = gmdate('D, d M Y H:i:s', filemtime($this->filePath)) . ' GMT';    $etag = sprintf('w/"%s:%s"', md5($lastModified), $this->fileSize);    $ranges = $this->getRange();    // headers    header(sprintf('Last-Modified: %s', $lastModified));    header(sprintf('ETag: %s', $etag));    header(sprintf('Content-Type: %s', $this->mimeType));    $disposition = 'attachment';    if (strpos($this->mimeType, 'image/') !== FALSE) {     $disposition = 'inline';    }    header(sprintf('Content-Disposition: %s; filename="%s"', $disposition, basename($this->filePath)));    if ($ranges != null) {     if ($this->isLog) {      $this->log(json_encode($ranges) . ' ' . $_SERVER['HTTP_RANGE']);     }     header('HTTP/1.1 206 Partial Content');     header('Accept-Ranges: bytes');     header(sprintf('Content-Length: %u', $ranges['end'] - $ranges['start']));     header(sprintf('Content-Range: bytes %s-%s/%s', $ranges['start'], $ranges['end'], $this->fileSize));     //     fseek($fileHande, sprintf('%u', $ranges['start']));    } else {     header("HTTP/1.1 200 OK");     header(sprintf('Content-Length: %s', $this->fileSize));    }    // read file    $lastSize = 0;    while (!feof($fileHande) && !connection_aborted()) {     $lastSize = sprintf("%u", bcsub($this->fileSize, sprintf("%u", ftell($fileHande))));     if (bccomp($lastSize, self::BUFF_SIZE) > 0) {      $lastSize = self::BUFF_SIZE;     }     echo fread($fileHande, $lastSize);     ob_flush();     flush();    }    set_magic_quotes_runtime($magicQuotes);    ob_end_flush();   }   if ($fileHande != null) {    fclose($fileHande);   }  }  /**   * 设置记录   * @param <Boolean> $isLog 是否记录   */  public function setIsLog($isLog = true) {   $this->isLog = $isLog;  }  /**   * 记录   * @param <String> $msg 记录信息   */  private function log($msg) {   try {    $handle = fopen('transfer_log.txt', 'a');    fwrite($handle, sprintf('%s : %s' . PHP_EOL, date('Y-m-d H:i:s'), $msg));    fclose($handle);   } catch (Exception $e) {    // null;   }  } }