Using Spring Boot with Jersey

Simple Application with Spring Boot and Jersey

Spring Boot is a bootstrapping framework for Spring applications. It has seamless support for integrating with Jersey also. One of the advantages of this (from the perspective of a Jersey user), is that you have access to Spring’s vast ecosystem.

To get started, create a new standalone (non-wepapp) Maven project. We can create a webapp also, but for this guide, we will just use a standalone app. Once you’ve create the project, add the following to your pom.xml

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
</properties>
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.4.0.RELEASE</version>
</parent>
<dependencies>  
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jersey</artifactId>
    </dependency>
    <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-tomcat</artifactId>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

We just need two dependencies. One for the Jersey Spring Boot module, and another for an embedded Tomcat server. The plugin we will use to run the application to test.

Once you have that, add the following classes to the project.

com/example
  |
  +-- GreetingApplication.class
  +-- JerseyConfig.class
  |
  + com/example/services
  |   |
  |   +-- GreetingService.class
  |   +-- NiceGreetingService.class
  |
  + com/examples/resources
      |
      +-- GreetingResource.class

GreetingApplication.class

This is the bootstrap class (very simple)

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class GreetingApplication {
    
    public static void main(String[] args) {
        SpringApplication.run(GreetingApplication.class, args);
    }
}

JerseyConfig.class

This is the Jersey configuration class

import javax.ws.rs.ApplicationPath;
import org.glassfish.jersey.server.ResourceConfig;
import org.springframework.stereotype.Component;

@Component
@ApplicationPath("/api")
public class JerseyConfig extends ResourceConfig {
    public JerseyConfig() {
        packages("com.example");
    }
}

GreetingService.class and NiceGreetingService.class

public interface GreetingService {
   public String getGreeting(String name);
}

import org.springframework.stereotype.Component;

@Component
public class NiceGreetingService implements GreetingService {
    
    @Override
    public String getGreeting(String name) {
        return "Hello " + name + "!";
    }
}

GreetingResource

This is the resource class where we will let Spring inject the GreetingService into.

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import org.springframework.beans.factory.annotation.Autowired;
import com.example.service.GreetingService;

@Path("greeting")
public class GreetingResource {

    private GreetingService greetingService;

    @Autowired
    public GreetingResource(GreetingService greetingService) {
        this.greetingService = greetingService;
    }

    @GET
    public String getGreeting(@QueryParam("name") String name) {
        return this.greetingService.getGreeting(name);
    }
}

And that’s it. We can now run the application. Grab a terminal and run the following command from the root of the project.

mvn spring-boot:run

The application should take a few seconds to get started. There will be some logging, and you will see some Spring ASCII art. After that art, it should be about 30 lines or so of more logging, then you should see

 15.784 seconds (JVM running for 38.056)

Now the app is started. If you use cURL you can test it with

curl -v 'https://localhost:8080/api/greeting?name=peeskillet'

If you are on Windows, use double quotes around the URL. If you aren’t using cURL, just type it in the browser. You should see the result

Hello peeskillet!

You may notice the request takes a few seconds on the first request you make. That is because Jersey is not fully loaded when the app launches. We can change that by adding a application.properties file in the src/main/resources folder. In that file add the following:

spring.jersey.servlet.load-on-startup=1