html>
head>
 meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
 title>文件上传Demo/title>
/head>
body>
form method="post" action="upload.php" enctype="multipart/form-data">  
 table border=0 cellspacing=0 cellpadding=0 align=center width="100%">  
 tr>  
  td width=55 height=20 align="center">
  input type="hidden" name="MAX_FILE_SIZE" value="2000000">文件： 
  /td>  
  td height="16">  
  input name="file" type="file" value="浏览" />       
  input type="submit" value="上传" name="submit" />  
  /td>  
 /tr>  
 /table>  
/form>
/body>
/html>

?php
/**
 * @title 文件上传示例
 * @author FeoniX
 */
header("Content-Type:text/html; charset=utf-8");
if($_POST['submit']){
 $upfiles = new Upload();
 $upfiles->upload_file();
}
class Upload{
 public $upload_name; //上传文件名
 public $upload_tmp_name; //上传临时文件名
 public $upload_final_name; //上传文件的最终文件名
 public $upload_target_dir; //文件被上传到的目标目录
 public $upload_target_path; //文件被上传到的最终路径
 public $upload_filetype ; //上传文件类型
 public $allow_uploadedfile_type;//允许的上传文件类型
 public $upload_file_size; //上传文件的大小
 public $allow_uploaded_maxsize=10000000;//允许上传文件的最大值
 //构造函数
 public function __construct()
 {
 $this->upload_name = $_FILES["file"]["name"]; //取得上传文件名
 $this->upload_filetype = $_FILES["file"]["type"];
 $this->upload_tmp_name = $_FILES["file"]["tmp_name"];
 $this->allow_uploadedfile_type = array('jpeg','jpg','png','gif','bmp','doc','xls','csv','zip','rar','txt','wps');
 $this->upload_file_size = $_FILES["file"]["size"];
 $this->upload_target_dir="./upload";
 }
 //文件上传
 public function upload_file()
 {
 $upload_filetype = $this->getFileExt($this->upload_name);//获取文件扩展名
 if(in_array($upload_filetype,$this->allow_uploadedfile_type))//判断文件类型是否符合要求
 {
  if($this->upload_file_size  $this->allow_uploaded_maxsize)//判断文件大小是否超过允许的最大值
  {
  if(!is_dir($this->upload_target_dir))//如果文件上传目录不存在
  {
   mkdir($this->upload_target_dir);//创建文件上传目录
   chmod($this->upload_target_dir,0777);//改权限
  }
  $this->upload_final_name = date("YmdHis").rand(0,100).'.'.$upload_filetype;//生成随机文件名
  $this->upload_target_path = $this->upload_target_dir."/".$this->upload_final_name;//文件上传目标目录
  if(!move_uploaded_file($this->upload_tmp_name,$this->upload_target_path))//文件移动失败
  {
   echo "font color=red>文件上传失败！/font>";
  }
  else
  {
   echo "font color=green>文件上传成功！/font>";
  }
  }
  else
  {
  echo("font color=red>文件太大,上传失败！/font>");
  }
 }
 else
 {
  echo("font color=red>仅支持一下文件类型，请重新选择：br>".implode('，',$this->allow_uploadedfile_type)."/font>");
 }
 }
  /**
   *获取文件扩展名
   *@param String $filename 要获取文件名的文件
   */
  public function getFileExt($filename){
   $info = pathinfo($filename);
   return @$info["extension"];
  }
}
?>