如何模拟离线 Spring Boot 应用程序

Question

I have a Controller with an endpoint. I would like to disable this endpoint at runtime so that it looks like the application is offline for the user.

Currently doing this to disable the endpoint:

private static final Map<RequestMappingInfo, HandlerMethod> requestMappings = new HashMap<>();

this.context.getHandlerMethods().forEach((k, v) -> {
    if (k.getPatternsCondition().getPatterns().contains("/customer")) {
      requestMappings.put(k, v);
    }
});
requestMappings.forEach((k, v) -> this.context.unregisterMapping(k));

And this to enable:

requestMappings.forEach((k, v) -> this.context.registerMapping(k, v.getBean(), v.getMethod()));
requestMappings.clear();

This works like a charm, the beans are unregistered and registered at runtime. However when the user calls my application they get a 404 instead of a Connection timed out, which is what I was looking for.

I do understand why I am getting a 404. Requests still enter the application but the path isn't found because the beans aren't registered so it return sa 404. How do I go about tackling an "actual offline" situation that doesn't return anything at all.

Answer 1

I don't really understand what can be a use-case for such a scenario.

There are some approaches I can think of though:

1. Just stop the application. As was already stated in comments - the client will try to connect and will eventually run into connection timeout.

2. Restart the application context "programmatically" without restarting the whole JVM. There is a tutorial about doing this.

The second approach can be appealing only in conjunction with a property spring.main.web-environment=false that you should supply during the application context restart.