13 Using WebClient to make API calls - Spring Boot Microservices Level 1
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- เผยแพร่เมื่อ 12 ก.พ. 2019
- In this video, we'll switch to using WebClient for making API calls. We'll explore how WebClient uses reactive programming constructs for fetching API response.
Workshop recorded live on Feb 9, 2019.
Course: Spring Boot Microservices Level 1 - Communication and discovery
This course introduces you to building microservices with Spring Boot and Spring cloud. This is Level 1 - start here if you are completely new to building microservices in Spring.
Sync and Async are like in the post office.
Sync - When you go to take your package you wait inline till your number comes and
then you are served (wasting time and stopping all your daily tasks).
Async - you get your number via SMS and you keep with the rest of the
day and when your turn arrives you get a message on your phone to come
and get your package.
Wonderful analogy. Thanks
He is really good teacher. Very unique style of explaining.
like all your videos, right to the point, super well explained. QUALITY!
Wonderful job! Thanks a lot for such a clear explanation.
Awesome tutorial....you're great as always! Txs :)
These days when workshops could be made with other people in the same room....So great...So good...
Awesome content! It's perfect for who wants to learn a little bit about microservices
truely amazing tutorial!
Very easy and straightforward , i like the way
Awesome tutorial! Great teaching!
AMAZING Workshop!!!!!!!!!!!! THANK YOU!!!!!!!!!!!
You are awsome, thanks for taking care of teaching us the new way of WebClient instead of using the deprecated RestPattern :)
Excellent work, you are a good man and I wish you the best.. Thank you very much.
Cant wait for the workshop with WebClient =D
You couldn't have explained it better.
Thanks!
Amazing explanation, thank you very much. This seems easier than Retrofit.
Awesome Kaushik, You are doing a great job.
Wonderful job! Thank you!.
Your are great Sir ,the way of teaching is awesome
You are ultimate sir, thank you...!
Thanks for this great tutorial!
Brilliant explanation !!
Very good illustration..
Big thanks to this man!
awesome tutorials sir..
Thank you so much for this
Thanks lot for this excellent video
Thanks it's very helpful
Learned as well as enjoyed all the videos in this series. In video 13 at 11.30, I think you can relate it with callable Future in java executer framework wherein we get the actual object returned by call after thread execution finishes by future.get () method in asynchronous way.
Super sir...... Thanks a lot:)
Very understandable, thanks
This channel has the most distracting content , when ever I visit this channel looking for a solution , I always get carried away by the content that is not necessary for that particular instance of time . Great Work!!!!!
so tru😂
His shirt changed instantly. Wow that's magic😁.... btw loving this series so far.
Awesome very nice !!
Great stuff
Just one correction I guess. 10:51 here the word "Mono" doesn’t really refer to the promise aspect of the async call, rather as the name suggests, all it means is the response value, if at all, is going to be a singular value and not a list of values (which again is called "Flux" in this whole sping reactive web ecosystem). This distinction is very important to the functional programming paradigm and hence its introduction to this ecosystem as well.
you can get a List as a Mono
love it.
BodyToMono is like a McDonald's receipt. At the store when you order your food, the cashier prints out a receipt with an order number on it and hands it over to you (A promise that you will get your food). The order is routed to kitchen for preparation while you are waiting for your food to be cooked (A fetch, a db query, a file read in our case), and when the food is ready, the cashier calls your number and voila, you got your food (a db result, a json response from an api call). What I am not clear is what if request is rejected? Say my burger type is sold out and kitchen responds that we don't have such meat available anymore? How does it work in the case of BodyToMono?
Can we configure our producer api to send the result say JSON with some parameters set like 'error : cannot process the request because blah blah' and then at consumer side, the model will have that field which matches that parameter and gets built by bodyToMono?
Awesome explanation . Hope we have a Work Shop on the WebClient Async ....
thanks dude.
Nice episodes man, really nice how you explain those things.
Koushik, thanks for the great videos. Your videos are just WONDERFUL resources. You mentioned about RxJava workshop in this video. Do you have any plans to do it?
Hi Kaushik, You have AsyncRestTemplate already for async calls . Can you please explain us the difference between ASyncRestTemplate Vs WebClient ?
Great Work, Crystal Clear. But i have a question regarding performance of webclient in synchronous calls comapred to that of rest template?
Thank you.
great tutorial, help me so much!
I looking for it but cant found in other places!
I've a question, what if we've a kafka topic that we consume from and want to make a rest post, and the service that produces to this is faster than the rest post request. Will a webclient work faster than a regular resttemplate and will the service still have to wait for the response before committing offsets in the kafka topic?
nicely explained
Give this men a bells🥃
Shouldn't be the return value of .build() from the web client builder specified as @Bean ? as invoking .build() will create instance every time a new request comes?
After a long time I could see and learn something valuable... very great content and very good organization.... but I think if you add a separate level 4 and level 5 for webclient and api gateway it will be great
This is really much needed for people who wanted to learn web client properly and api gateway
I have started recommending this channel to others to learn something from here
Thanks for your videos. C# dev here, trying to catch up on everything I’ve missed out on in Java since 1995. Does Java itself have a better word or moniker for the concept of a future or promise? Mono seems like a terrible word for that, or is it just me? What am I missing? Does Java have an async/await mechanism like c# or Js?
What happens when we have multiple class into service stub and we got request as string then how can we mapping class name ?
bodyTomono(?)
I have a question when we write .block() at the end does this means that we are blocking the thread or it means we are writing in a synchronous fashion like async-await in javascript
Hello Kaushik, Great work explaining each and every minute detail, thank you !! Could you also please share the repository link of this code?
Very thanks for nice explain
Please question, for call web service, as performance(fast, memory, CPU) which better, Client Jersey or WebClient Spring??
We can use Reactive Programming with SGBDR like Oracle don't think so cause it's compatible with cassandra mongoDB and other no sql sgbd is it true ?
i like hearing the sound of the keyboard clicks in this video. it's peaceful. hahahahaa.
Thanks ! How can we get the status code of the response ? and why the webclient running very slow with my local Java 11 and spring 5 ?
Hello, I have one question. In microservice design, and interservice communication. How to pass authorization header(JWT token) from microservice A to microservice B in WebClient call? But to avoid setting header every time in each web client request.
Should we have created a WebClient bean with WebClient.builder().build() instead of a builder bean so that we would reuse that same instance of WebClient for all our api calls?
i have the same doubt
Yep, there's nothing request-specific to the client instance being built.
Check if that is thread safe, it is quite possible your instance is serving a request and it is handed over to next incoming request, it might get corrupted and you will get unexpected and unwanted results. Please reply your findings if you already have tried this, its been 2 years you asked this question.
if i replace Movie.class in body to mono, to String.class, will it return me the string which i want ?
Hi
thanks for your video.
how does one include body in his request. I m using the init method to build my base url and then I am creating a method to do a get operation.
I placed my headers as default in the init method and then I want to build a body in order to snd request to the token creation endpoint
It doesnt seem smooth to me. How is it done?
Thanks a lot Koushik..!!
could anybody please share the link to learn asynchronous reactive programming using webClient ; if Koushik has already posted?
if not Koushik please try to make a series on Async programming in java springboot.
Thanks in advance.
you are making singleton but what happen if a try to hit same end point at same point from different browsers?
Is there any example of consuming https url using webclient ? Getting SSL erros.
@Kaushik, when to use .block() and not to?
what's the benefit of using WebClient with block mechanism vs traditional RestTemplate?
How do I get back a collection of items? or a nested json object if the API collects that.
Can we make asynchronous call( using webclient) between two applications.
Thanks for the great video. In my case, when I am trying to use block() to make the call synchronous, I get the following error: java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-4
No idea on how to fix that :/
It is explained here: stackoverflow.com/questions/64838936/how-to-use-spring-webclient-to-make-synchronous-call/64845627#64845627
I understand what you explained..
But how's it Asynchronous....how webclient is asynchronous....couldnt get....it's is still blocking and after getting result moving forward.....
Hi Kaushik..Can you please make a video on asynchronous and reactive programming
Kindly make playlist on reactive programming with web flux and mysql db
As of now, using web flux with mysql is futile. Mysql JDBC driver for Java is synchronous by default and last time I checked Oracle hasn't made any declaration about making an asynchronous JDBC driver for MySql. So You can actually use Web flux with MySql but the db calls won't be async. Although there's a workaround with a third party driver called Jasync but that's not very useful as you don't have Spring Data JPA support for that.
how you're going to call WebClient from other technology such as React.js
Great stuff. However, isn't calling `block()` blocking the execution after *every request*? Why not make them all and then block until they all resolve (eg, the JS `Promise.all()` way)? Or am I misunderstanding this? :D
OK, found the way to make the calls in parallel using `Mono.zip` method.
How can we put request params and request body or header in api request from spring boot
consider using Retrofit instead of RestTemplate/webclient to get nice and clean code
To me the question is how you mock this web clients? for example with Mockito....
How to cache the response we get from the service call which we make via webclient??
Please prepared a series on spring boot reactive programming
can you make a video on WebSockets, sir!
It's not working for me it's giving dns query timeout exception .. could you please tell why am I getting this error?
Any example of Webclient with SSL (one way or two way SSL)?.
So I guess in this scenario after using block() there is actually no difference in restTemplate and WebClient
its a great series but i want to point to something.
I think we shouldn't block at all as this kills the purpose of using reactive programing
you can change the type of -ratings- to a flux
and use ratings.flatmap(rating -> ... )
and then inside the flatMap() after .bodytoMono().map(movie -> new CatalogItem(...)); and return that.
He is not doing reactive programming
@@anarodriguezfernandez75 he pointed to that in the following videos
No
Use of mono is still not clear ..you are using block...how it is better then resttemplate? After get call api call thread is waiting or dead?
I wanted to know how to store the data after consuming the api to database
It was great explanation...but how we will remember all these stuff that you have explained in all the videos🙂😀
I am getting nullpointer exception. Any suggestions?
Any playlist from Javabrain - on reactive programing
Can we use WebClient for APIs over HTTP2?
Is there a tutorial about spring webflux by java brain here?
How can we setup proxy? Need to access third party services
Well if you have a experinece with node js ,Mono is basically a promise in node js
What is the springboot version here?
I'm getting io.connection refused exception while calling other microservice. Does anyone knows how to fix it
hey did u get soln
Could not autowire. There is more than one bean of 'Builder' type.
Beans:
getBuilder (MovieCatalogServiceApplication.java) webClientBuilder (WebClientAutoConfiguration.class)
Netty is a server right? How Netty and Tomcat are running togethar?
Could anyone please help me out to understand the following statement -
new Rating(movieId: "1234", rating:4);
"movieId:" and "rating:" are hints from IDE and they are not in actual code.
So it's actually just: new Rating("1234", 4);