Within the simulator services layer, a "transaction" key is extracted from the request object, and will be used to determine the specific XML file to retrieve, consume, and return as a POJO response.

在模拟器服务层内部，从请求对象中提取出“transaction”键，然后使用它来指定将要检索、使用并作为POJO响应返回的XML文件。

youdao

The smart phone is key, because it enables not only the transaction but also getting the customer into the car.

FORBES: New Company Rents Your Car By The Hour

That stops a thief who intercepts a key and tries to use it in a fraudulent transaction.

FORBES: Magazine Article

For the transaction banks, controlling costs per trade and costs per asset under management will become the key to profitability.

FORBES: Are Bankers Competent to be Running Banks?