Introduction

This page describes how CXF JAX-RS Client code can be used inside SpringBoot applications.

Please see a CXF JAX-RS starter section on how to enable JAX-RS endpoints.

Setup

If your SpringBoot Application depends on a CXF JAX-RS starter then no more dependencies are required.

If you'd like to run JAX-RS clients in a pure client-side SpringBoot Application then the following Maven pom should suffice in many cases:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
    http://maven.apache.org/xsd/maven-4.0.0.xsd">
    
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.5.RELEASE</version>
    </parent> 
    <artifactId>spring-boot-cxf-client-application</artifactId>
    <groupId>org.apache.cxf.samples</groupId>
    <version>3.1.11</version>
    <name>Spring Boot CXF Client Application</name>
    <description>Spring Boot CXF Client Application</description>
    
    <properties>
        <cxf.version>3.1.11</cxf.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-rt-rs-client</artifactId>
            <version>${cxf.version}</version>
        </dependency>
    </dependencies>
    <build>
      <plugins>
        <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
           <configuration>
               <mainClass>sample.rs.client.SpringBootClientApplication</mainClass>
           </configuration>  
        </plugin>
       </plugins>
    </build>
</project>

Enabling WebClients

WebClient can be auto-wired with the help of EnableJaxRsWebClient annotation.

JAX-RS providers (annotated with @Provider) and marked as Spring Components are added to WebClient. The providers which are not marked as Spring Components can also be optionally auto-discovered. WebClient can also be configured with optional headers such as Accept and Content-Type and made thread-safe.

package sample.rs.client;

import org.apache.cxf.jaxrs.client.WebClient;
import org.apache.cxf.jaxrs.client.spring.EnableJaxRsWebClient;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@EnableJaxRsWebClient
public class SpringBootClientApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootClientApplication.class, args);
    }
  
    @Bean
    CommandLineRunner initWebClientRunner(final WebClient webClient) {
      
      return new CommandLineRunner() {

        @Override
        public void run(String... runArgs) throws Exception {
            System.out.println(webClient.path("sayHello/ApacheCxfWebClientUser").get(String.class));
        }
      };
    }
    
}

Enabling ProxyClients

Proxy Clients can be auto-wired with the help of EnableJaxRsProxyClient annotation.

It creates a proxy from the auto-discovered service class interface.

JAX-RS providers (annotated with @Provider) and marked as Spring Components are added to proxy clients. The providers which are not marked as Spring Components can also be optionally auto-discovered. Proxy can also be configured with optional headers such as Accept and Content-Type (if JAX-RS @Produces and/or @Consumes are missing or need to be overridden) and made thread-safe.

package sample.rs.client;

import org.apache.cxf.jaxrs.client.spring.EnableJaxRsProxyClient;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

import sample.rs.service.HelloService;

@SpringBootApplication
@EnableJaxRsProxyClient
public class SpringBootClientApplication {
    
    public static void main(String[] args) {
        SpringApplication.run(SpringBootClientApplication.class, args);
    }
 
    @Bean
    CommandLineRunner initProxyClientRunner(final HelloService client) {
      
      return new CommandLineRunner() {

        @Override
        public void run(String... runArgs) throws Exception {
            System.out.println(client.sayHello("ApacheCxfProxyUser"));
        }
      };
    }
}

If you prefer to specify a proxy service interface directly in the client code you can drop EnableJaxRsProxyClient annotation and provide a simple JaxRsProxyClientConfiguration extension instead:

package sample.rs.client;

import org.apache.cxf.jaxrs.client.spring.JaxRsProxyClientConfiguration;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import sample.rs.service.HelloService;

@SpringBootApplication
public class SpringBootClientApplication {
    
    public static void main(String[] args) {
        SpringApplication.run(SpringBootClientApplication.class, args);
    }
 
    @Bean
    CommandLineRunner initProxyClientRunner(final HelloService client) {
      
      return new CommandLineRunner() {

        @Override
        public void run(String... runArgs) throws Exception {
            System.out.println(client.sayHello("ApacheCxfProxyUser"));
        }
      };
    }
    
    @Configuration
    static class HeloServiceConfiguration extends JaxRsProxyClientConfiguration {
        @Override
        protected Class<?> getServiceClass() {
            return HelloService.class;
        }
    }
}

Discovery of Service Endpoints

Discovery of JAX-RS endpoint addresses published to a well-known service registries such as Netflix Eureka Registry is shown in a JAX-RS Spring Boot Scan demo.

This is achieved with the help of CXF Failover and/or LoadBalancing features.

Configuration

The configuration properties apply to both WebClient and Proxy configurations.

cxf.jaxrs.client.address is a required property which identifies a target address.

cxf.jaxrs.client.thread-safe property can be set to true to make the clients thread-safe.

cxf.jaxrs.client.headers.accept property can be used to set HTTP Accept header.

cxf.jaxrs.client.headers.content-type property can be used to set HTTP Content-Type header.

cxf.jaxrs.client.classes-scan-packages property can be used to auto-discover JAX-RS service class interfaces (for proxies) and providers for proxies and web clients.