Thinkphp 导出大量数据 csv格式

public function test2() {
		$user_count = M('department')->count();

		$page = ceil($user_count / 10000);

		$fp = fopen('c:\file.csv', 'w');
		for ($p = 1; $p <= $page; $p++) {

			$user = M('department')->page($p . ',10000')->select();

			foreach ($user as $fields) {

				foreach ($fields as $i => $v) {

					$fields[$i] = iconv('utf-8', 'gbk', $v);
				}

				fputcsv($fp, $fields);
			}

			unset($user);
		}

		fclose($fp);

	}