How does java avoid sending SMS repeatedly?

In my humble opinion, the current e-commerce platform can adopt SOA architecture, or simply put, the SMS module can be extracted separately. Then it is called by means of communication such as webservice to ensure the uniqueness of the short message exit.

In addition, it is a better choice to use Message Queuing (MQ), which can ensure the uniqueness and security of data, and avoid sending short messages repeatedly through MQ's transaction mechanism. And even if the background is abnormal, as long as things are not submitted, the data in MQ can be guaranteed not to be lost, and SMS can still be sent after the system is restored.