例子一：

/**
 * 多文件上传
 * 
 * @author Dream <dream@shanjing-inc.com>
 */
public function multiple_uploads() {
  //载入所需类库
  $this->load->library("upload");
  
  //配置上传参数
  $upload_config = array(
      "upload_path"  => "",
      "allowed_types" => "jpg|png|gif",
      "max_size"   => "500",
      "max_width"   => "1024",
      "max_height"  => "768",
  );
  $this->upload->initialize($upload_config);
    
  //循环处理上传文件
  foreach ($_FILES as $key => $value) {
    if (!empty($key["name"])) {
      if ($this->upload->do_upload($key)) {
        //上传成功
        print_r($this->upload->data());
      } else {
        //上传失败
        echo $this->upload->display_errors();
      }
    }
  }
}

例子二：

function upload() {
    $config["upload_path"] = "./uploads/"; 
    /*这里的uploads是相对于index.php的,也就是入口文件,这个千万不要弄错哦!
    否则就会报错"The upload path does not appear to be valid."; 
    */
    $config["allowed_types"] = "gif|jpg|png";
    /*我试着去上传其它类型的文件,这里一定要注意顺序! 
    A problem was encountered while attempting to move the uploaded file to the final destination.
    这个错误一般是上传文件的文件名不能是中文名,这个很郁闷!还未解决,大家可以用其它方法,重新改一下文件名就可以解决了! 
    $config["allowed_types"] = "zip|gz|png|gif|jpg";(正确)
    $config["allowed_types"] = "png|gif|jpg|zip|gz";(错误)
    */
    $config["max_size"] = "1024";
    $config["max_width"] = "1024";
    $config["max_height"] = "768";

    $config["file_name"] = time(); //文件名不使用原始名
    $this->load->library("upload", $config);
    if(!$this->upload->do_upload()) {
        echo $this->upload->display_errors();
    }else{

       $data["upload_data"]=$this->upload->data(); //文件的一些信息
       $img=$data["upload_data"]["file_name"]; //取得文件名

       echo $img."<br>";

       foreach($data["upload_data"] as $item => $value){
       echo $item.":".$value."<br>";

      }

    }
}