public function excel_put(){
  //先做一個文件上傳，保存文件
  $path=$_FILES['file'];
  $filePath = "uploads/".$path["name"];
  move_uploaded_file($path["tmp_name"],$filePath);
  //$data=array('B'=>'name','C'=>'pwd','D'=>'money1','E'=>'salt');
  $data=array('B'=>'name','C'=>'pid');
  $tablename='city2';//表名字
  $this->excel_fileput($filePath,$data,$tablename);
}

private function excel_fileput($filePath,$data,$tablename){
  $this->load->library("phpexcel");//ci框架中引入excel類
  $PHPExcel = new PHPExcel();
  $PHPReader = new PHPExcel_Reader_Excel2007();
  if(!$PHPReader->canRead($filePath)){
    $PHPReader = new PHPExcel_Reader_Excel5();
    if(!$PHPReader->canRead($filePath)){
      echo 'no Excel';
      return ;
    }
  }
  // 加載excel文件
  $PHPExcel = $PHPReader->load($filePath);
  // 讀取excel文件中的第一個工作表
  $currentSheet = $PHPExcel->getSheet(0);
  // 取得最大的列號
  $allColumn = $currentSheet->getHighestColumn();
  // 取得一共有多少行
  $allRow = $currentSheet->getHighestRow();
  // 從第二行開始輸出，因為excel表中第一行為列名
  for($currentRow = 2;$currentRow <= $allRow;$currentRow++){
    /**從第A列開始輸出*/
    //echo $allColumn;
    for($currentColumn= 'A';$currentColumn<= $allColumn; $currentColumn++){
      $val = $currentSheet->getCellByColumnAndRow(ord($currentColumn) - 65,$currentRow)->getValue();
      //print_r($val);
      //die;
      if($currentColumn == 'A')
      {
        //echo $val."\t";
      }else if($currentColumn <= $allColumn){
        $data1[$currentColumn]=$val;
      }
    }
    foreach($data as $key=>$val){
      $data2[$val]=$data1[$key];
    }
    $this->db->insert($tablename,$data2);
    //print_r($data2);
    //echo "</br>";
  }
  //echo "\n";
  echo "導入成功";
}

public function excel_out(){
  header("Content-type:text/html");
  header("Content-Disposition:attachment;filename=123.xls");
  $array=$this->db->get("city")->result_array();
  $str="id\t"."name\t"."pid\n";
  foreach($array as $val){
    $str.=$val['id']."\t".$val['name']."\t".$val['pid']."\n";
  }
  echo $str;
}