PHP：使用phpexcel阅读xls

Question

我无法读取.xls文件。值被读取为null和未知字符。该文件是从ftp服务器下载的，并且受到保护

invoice={
            "invoicefile":(open(full_filename, "rb")),
            "debtor":"5560360793",
            "amount":"55000",
            "serial":"1234567890",
            "dateout":"20180728",
            "expiration":"20180808",
        }
        response=self.client.post(reverse("invoiceupload"), invoice)
        self.assertEqual(response.status_code, 201)

转换后的文件如下图所示：