HTML+PHP实现多文件上传

<form id="form1" name="form1" enctype="multipart/form-data" action="upload.php" method="post">
   <div class="form-group">
     <input type="file" id="fileupload" name="files[]" class="form-control-file" multiple="multiple">
   </div>
   <button type="submit" class="btn btn-primary">开始上传</button>
 </form>

#从POST中取出文件信息
$file = $_FILES['files'];

if(!is_null($file) and is_array($file['name'])){
#上传了多个文件
  
  #判断文件个数
  $file_num = count($file['name']);
  
  #上传目录
  $upload_path = $_SERVER['DOCUMENT_ROOT'] . "/upload/";
  
  #用for循环逐个保存文件
  for($i=0; $i<$file_num; $i++){
  
    #用时间和随机数起新的名字，避免重名
    $new_file_name = date("Ymd") . "_" .rand(10000, 99999) . "." . end(explode('.', basename($file['name'][$i])));
    
    #从临时文件/tmp/xxx移到指定上传目录    
    if(move_uploaded_file($file['tmp_name'][$i], $upload_path . $new_file_name)){
      #输出上传后的文件路径，方便用户复制粘贴
      echo "<p>";
      echo "  <span>[" . $file['name'][$i] . "](http://iccircle.com/upload/" . $new_file_name . ")</span>";
      echo "  <span><a href='http://iccircle.com/upload/" . $new_file_name . "' target='_blank'>预览</a></span>";
      echo "</p>";
    }else{
      echo "<p>fail</p>";
    }
  }
  
}else if(!is_null($file) and is_string($file['name'])){
#上传了单个文件，单个文件时数据不是数组的形式，只是字符串，所以单独处理

  $upload_path = $_SERVER['DOCUMENT_ROOT'] . "/upload/";

  $new_file_name = date("Ymd") . "_" .rand(10000, 99999) . "." . end(explode('.', basename($file['name'])));
  if(move_uploaded_file($file['tmp_name'], $upload_path . $new_file_name)){
    echo "<p>";
    echo "  <span>[" . $file['name'] . "](http://iccircle.com/upload/" . $new_file_name . ")</span>";
    echo "  <span><a href='http://iccircle.com/upload/" . $new_file_name . "' target='_blank'>预览</a></span>";
    echo "</p>";
  }else{
    echo "<p>fail</p>";
  }
}