php上传文件与图片重命名方法总结

$name=$_FILES['userfile']['name'];   //将所上传的文件名称赋予name

//文件名的自动生成

list($usec, $new_name) = explode(" ", microtime());

if(@$extension_name){//限制文件类型为jpg、gif、png、bmp

move_uploaded_file($tmp_name,$new_dir.'/'.$new_name.'.'.$extension_name);//移动到目标文件夹

echo '上传成功';

$date = date(ymdhis);
//echo($date);
if ((($_FILES["uppic"]["type"] == "image/gif")
|| ($_FILES["uppic"]["type"] == "image/jpeg")
|| ($_FILES["uppic"]["type"] == "image/pjpeg"))
&& ($_FILES["uppic"]["size"] < 2000000))
{
if ($_FILES["uppic"]["error"] > 0)
    {
    echo "Return Code: " . $_FILES["uppic"]["error"] . "
";
    }
else
    {
    //echo "Upload: " . $_FILES["uppic"]["name"] . "
";
    //echo "Type: " . $_FILES["uppic"]["type"] . "
";
    //echo "Size: " . ($_FILES["uppic"]["size"] / 1024) . " Kb
";
    //echo "Temp file: " . $_FILES["uppic"]["tmp_name"] . "
";
   $uptype = explode(".", $_FILES["uppic"]["name"]);
   $newname = $date.".".$uptype[1];
   //echo($newname);
   $_FILES["uppic"]["name"] = $newname;

    if (file_exists("pics/" . $_FILES["uppic"]["name"]))
      {
      echo $_FILES["uppic"]["name"] . " already exists. ";
      }
    else
      {
      $_FILES["uppic"]["name"] =
      move_uploaded_file($_FILES["uppic"]["tmp_name"],
      "pics/" . $_FILES["uppic"]["name"]);
      echo "";
      echo "";
      }
    }
}
else
{
echo "Invalid file";
}
?>