I am in a need of calling a api asynchronously in my spring boot application? Is there any methods that we can used in Spring RestTemplate?
RestTemplate may not be a good idea. As per documentation, AsyncRestClient exposes similar methods as RestTemplate, but returns ListenableFuture wrappers as opposed to concrete results. Also, WebClient would be a much better choice over AsyncRestClient which is deprecated. As the linked page shows it is
Deprecated. as of Spring 5.0, in favor of WebClient
Related
I am creating a Spring Boot MVC application, with Tomcat and JDBC. My app will be an API client, I've learned that I'll need RestTemplate class for API requests. But since Spring 5, RestTemplate is in maintenance mode and will be deprecated in the future.
The alternative is a WebClient class, which is powerful and useful for testing also. But it supports a reactive WebFlux stack.
For example, when I watched this tutorial on how to make tests with WebClient I was very confused:
https://www.youtube.com/watch?v=kGK9Hf8cnBw
I must use these Mono and Flux types?
My first question is, can I use WebClient to make a classic servlet-based app (with Tomcat, and JDBC/JPA like I used to)?
If not, what is an alternative to WebClient and RestTemplate?
WebClient can be used in synchronous style by blocking at the end for the result like this:
Person project = client.get().uri("/project/{id}", i).retrieve()
.bodyToMono(Project.class)
.block();
List<Person> projects = client.get().uri("/projects").retrieve()
.bodyToFlux(Project.class)
.collectList()
.block();
Here we use block() to block the stream and get the data out of it. Note that this shouldn’t be used in a reactive environment.
This is late but someone might benefit from this.. You can use open feign.. Check it out
which is better alternative for calling REST endpoint in springboot application, calling REST endpoints using WebClient or calling REST endpoints using RestTemplate ?
Spring’s documentation recommends using WebClient, but that’s only a valid recommendation for reactive apps. If you aren’t writing a reactive app, use OpenFeign instead. Like anything else in software, it fits well for some cases, but might complicate things for others. Choosing WebClient to implement the REST endpoint calls is strongly coupled to making your app reactive
RestTemplate gives many advantages if you are using it from within Springboot application, i.e. in your server side to another part of your own app - sort of like an internal call. Because the RestTemplate "knows" all your entities and beans and so if you need to send over or receive an object which is known within your springboot application RestTemplate can map them automatically which is a very nice advantage. If you sending a request to some third party api and do not pass or receive your known entities RestTemplate is still a valid option but it just becomes just another Http client. Its just simply there as part of Springboot provided tools. But in this case you may use any other client as well.
Does anyone know how to make Spring Data REST endpoints asynchronous?
I saw that we can add the annotation #Async with CompletableFuture<?> as returned object on the service methods.
But doing this, makes the use of the interface RepositoryRestResource pointless as we need to implement both the service and controller layers manually...
Or am I missing something here?
Currently Spring Data REST supports blocking I/O only. See this Jira Issue of Spring Data REST support for Spring WebFlux.
Spring MVC has an integration with Servlet 3.0 async request processing.
Although Spring MVC has async support, for non-blocking I/O, Spring WebFlux is recommended, because Spring WebFlux is async by design. See Spring Web MVC Async Request Compared to WebFlux
I am working on a microservice project where my individual spring boot microservices would be calling themselves and mainly to 3rd party API's to fetch and save data.
Since I am with legacy Spring boot application I can't think of replacing it with Reactor based Microservices.
But I am thinking of replacing My RestTemplate (using for communication with Other MS's and 3rd Party App) with new Spring Reactor Webclient to get some advantages of Async calls.
Is My use case a right candidate for Using Spring reactor WebClient?
Yes, composition of microservice and REST calls is a good use case for WebClient.
Plus Spring Boot 2 will let you combine the Spring MVC starter with the WebFlux starter and interpret that as "you want to run on the servlet stack, but might want to use WebClient sporadically".
There is a new implementation of http session for spring new reactive web flux api located here.
I would like to integrate the latest spring web session in the new spring reactive web flux. I can't seem to get it, I tried injecting it as a bean, but it does not work. I would like to inject it like I usually do with HttpSession
something like
#Autowired
Websession webSession;
Because Spring WebFlux is a reactive web framework, you can't expect the Web Session to be injected as a bean (even in the request scope). In the Servlet world, each request/response is processed in a single thread, which enables those approaches (i.e. the "request" scope). With WebFlux, a given request can be processed by multiple threads.
The WebSession instance associated with the current request/response is actually attached to the ServerWebExchange (see getSession). Because of the nature of the reactive programming model, you're very likely to access that session within a Reactor operator - so you can't expect to inject this instance somewhere else in your application.