[doc] Update Javadoc on RestTemplate/AsyncRestTemplate to highlight supported HTTP client libraries [SPR-13313]

[spring-projects-issues]

Stojan Sljivic opened SPR-13313 and commented

Is there any plan to support non blocking IO, Java NIO2, in AsyncRestTemplate?

Thanks

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Referenced from: commits bdf7351

[spring-projects-issues]

Rossen Stoyanchev commented

AsyncRestTemplate can be used with Apache HttpComponents and Netty clients both of which are non-blocking. Can you elaborate?

[spring-projects-issues]

Stojan Sljivic commented

Is there any example how AsyncRestTemplate can be used with Apache HttpComponents and Netty clients?

[spring-projects-issues]

Stojan Sljivic commented

OK, I just realized that there are several implementations of AsyncClientHttpRequestFactory (HttpComponentsAsyncClientHttpRequestFactory, Netty4ClientHttpRequestFactory, etc.).

It would be good to have at least some kind of javadoc in the AsyncRestTemplate that would point out to those implementations and provide some sample configurations. This way users are left to figure out everything from the code it self. I could be wrong, but I could not find any documentation about this.

[spring-projects-issues]

Rossen Stoyanchev commented

Fair enough. The type-level Javadoc should be more explicit about the range of underlying HTTP clients supported. It's an important thing to know up-front.