Overview
This Blog will see how we could use Spring WebFlux WebClient for making non-blocking HTTP requests.
What Is the WebClient?
Just put, the WebClient class which provides a common method for sending or receiving data from any local, intranet, or Internet resource which is identified by a URI. The WebClient class uses the WebRequest class which provides the access to resources. It is an interface that stands for the main entry point for performing web requests.
It was created as part of the Spring Web Reactive module and will be replacing the classic RestTemplate in these frameworks. Similarly, In addition, the new client is a reactive, non-blocking solution that works over the HTTP/1.1 protocol.
It’s very important to note that even though it is, in fact, a non-blocking client and it belongs to the spring-web flux library, the solution offers support for both synchronous and asynchronous operations, which makes it suitable also for applications running on a Servlet Stack.
This can be also achieved by blocking the operation to get the result. Of course, this practice is not recommended if we’re working on a Reactive Stack.
Lastly, the interface has a single execution, the DefaultWebClient class, which we’ll be working with.
WebClient — It is a non-blocking, reactive client to perform HTTP requests, and reveal a fluent, reactive API over underlying HTTP client libraries such as Reactor Netty.
We can use static factory methods create() or create(String), or builder() to build an instance.
For examples with a response body can see below:
– retrieve()
– exchangeToMono()
– exchange flux()
Below are examples with a request body see here:
– bodyValue(Object)
– body(Publisher, Class)
db.json
Start the command using Docker
docker run -d -p 8000:80 -v ${PWD}/db.json:/data/db.json clue/json-serverpom.xml
Post.java
Comment.java
Test class
All endpoints-
// all posts
http://localhost:8000/posts
// all comments
http://localhost:8000/comments
// post 1 comments
http://localhost:8000/posts/1/comments