如何在 Spring Boot 中持续接收和解析来自 REST API 的 JSON

Question

There is a remote server keep bringing about the data in JSON format. Here is a REST API named http://192.168.1.101:8000/v1/status ,and if I want to collect the data continuously in Spring Boot.Here is a possible JSON from the REST API:

{
"run-status": 0,
"opr-mode": 0, 
"ready": false, 
"not-ready-reason": 1, 
"alarms":["ps", "prm-switch"] 
}

I want to keep collecting or just subscribe the REST API, if there is a JSON and then collect it.

Answer 1

There are two main approaches of achieving what you are looking for:

1. Polling - If this service already exists and you do not have control over the code, then this might be your only option. You constantly poll the given URL to check if data has been changed.

   In spring, you can use @Scheduled annotation to execute and poll at any given frequency (using cron expression or fixed delays).

   https://www.baeldung.com/spring-scheduled-tasks - provides a detail of how to create a scheduled tasks.

2. Webhooks - If you have control over your server code, you can use webhooks to notify subscriber about availability of data. It is a callback mechanism where caller will receive a notification about data changes on the server, and subscriber can then call server to fetch data immediately.

More about Polling and Webhooks can be found on this URL: https://dzone.com/articles/webhooks-vs-polling-youre-better-than-this-1

Answer 2

Make a "while" cycle what calls your function then goes to sleep (if needed) for the time you want.

Or just while (true) {}