How to use the Spring WebClient with Jetty, instead of Netty?

Question

According to the documentation it is possible to use the Spring Reactive WebClient with a different server as Netty:

WebClient provides a higher level API over HTTP client libraries. By default it uses Reactor Netty but that is pluggable with a different ClientHttpConnector.

However, I was not able to find a way how to do this. If I simply change the dependency from Netty to Jetty like this:

compile('org.springframework.boot:spring-boot-starter-webflux') {
       exclude group: 'org.springframework.boot', module: 'spring-boot-starter-reactor-netty'
}
compile group: 'org.springframework.boot', name: 'spring-boot-starter-jetty', version: '2.0.0.M5'

my application will fail to start:

2017-10-30 15:40:43.328 ERROR 20298 --- [  restartedMain] o.s.boot.SpringApplication               : Application startup failed

java.lang.NoClassDefFoundError: reactor/ipc/netty/http/client/HttpClient

Obviously I need to do something more. But this github issue gives me the impression that WebClient cannot be used without Netty.

Is it possible to replace the Netty implementation of WebClient?

score 10 · Answer 1 · answered Oct 22 '19 at 14:11

10

Add dependency:

org.eclipse.jetty:jetty-reactive-httpclient:1.0.3

And then:

HttpClient httpClient = new HttpClient();
ClientHttpConnector connector = new JettyClientHttpConnector(httpClient);

WebClient webClient = WebClient.builder().clientConnector(connector).build();

Source: https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html#webflux-client-builder-jetty

answered Oct 22 '19 at 14:11

rgrebski

2,354
20
29

Any idea on what changes should I do for SSL based requests for the same migration? – damndemon Jun 27 '22 at 14:57
1

@damndemon haven't done that, but probably this snippet may be useful for you: https://sslcontext-kickstart.com/client/spring-webclient-jetty.html – rgrebski Jun 28 '22 at 08:50

score 3 · Accepted Answer · answered Oct 30 '17 at 17:14

Right now, in Spring Framework, WebClient has only one available ClientHttpConnector implementation, which is powered by Reactor Netty. This explains the current situation - using WebClient means you need Reactor Netty as a dependency.

Note that there's an existing issue about supporting Jetty Client as an alternative, see SPR-15092.

How to use the Spring WebClient with Jetty, instead of Netty?

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