Java Jersey 2: standalone?

Question

Is it possible to have a Jersey REST service standalone in a java application? Every example I find is in the context of a webcontainer (web.xml).

Thanks for help!

Answer 1

Just follow the Jersey docs getting started. It creates a standalone using Grizzly server. With Maven, you can easily create it with the following archetype command.

mvn archetype:generate -DarchetypeArtifactId=jersey-quickstart-grizzly2 \
-DarchetypeGroupId=org.glassfish.jersey.archetypes -DinteractiveMode=false \
-DgroupId=com.example -DartifactId=simple-service -Dpackage=com.example \
-DarchetypeVersion=2.27

The last argument -DarchetypeVersion can be replaced with any 2.x version you want. Currently, the latest is 2.27.

After running this command, you will have a generated main class you run from the command line.

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Another way is to use Spring Boot (which a lot of people are using), you can check out the official example and check out the docs

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Update

If you're not using Maven, below are all the jars that are pulled in with the archetype. Most are included in the Jersey RI bundle you download from the docs. Just figure out the ones that are not in the bundle and search for those.

I think the ones not included in the RI bundle DL, are

• grizzly-framework
• grizzly-http
• grizzly-http-server
• jersey-container-grizzly2-http

And here are all the generated classes from the archetype.

com.example.MyResource

package com.example;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

/**
 * Root resource (exposed at "myresource" path)
 */
@Path("myresource")
public class MyResource {

    /**
     * Method handling HTTP GET requests. The returned object will be sent
     * to the client as "text/plain" media type.
     *
     * @return String that will be returned as a text/plain response.
     */
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String getIt() {
        return "Got it!";
    }
}

com.example.Main

package com.example;

import org.glassfish.grizzly.http.server.HttpServer;
import org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpServerFactory;
import org.glassfish.jersey.server.ResourceConfig;

import java.io.IOException;
import java.net.URI;

/**
 * Main class.
 *
 */
public class Main {
    // Base URI the Grizzly HTTP server will listen on
    public static final String BASE_URI = "http://localhost:8080/myapp/";

    /**
     * Starts Grizzly HTTP server exposing JAX-RS resources defined in this application.
     * @return Grizzly HTTP server.
     */
    public static HttpServer startServer() {
        // create a resource config that scans for JAX-RS resources and providers
        // in com.example package
        final ResourceConfig rc = new ResourceConfig().packages("com.example");

        // create and start a new instance of grizzly http server
        // exposing the Jersey application at BASE_URI
        return GrizzlyHttpServerFactory.createHttpServer(URI.create(BASE_URI), rc);
    }

    /**
     * Main method.
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        final HttpServer server = startServer();
        System.out.println(String.format("Jersey app started with WADL available at "
                + "%sapplication.wadl\nHit enter to stop it...", BASE_URI));
        System.in.read();
        server.stop();
    }
}

(test) com.example.MyResourceTest

package com.example;

import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.WebTarget;

import org.glassfish.grizzly.http.server.HttpServer;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import static org.junit.Assert.assertEquals;

public class MyResourceTest {

    private HttpServer server;
    private WebTarget target;

    @Before
    public void setUp() throws Exception {
        // start the server
        server = Main.startServer();
        // create the client
        Client c = ClientBuilder.newClient();

        // uncomment the following line if you want to enable
        // support for JSON in the client (you also have to uncomment
        // dependency on jersey-media-json module in pom.xml and Main.startServer())
        // --
        // c.configuration().enable(new org.glassfish.jersey.media.json.JsonJaxbFeature());

        target = c.target(Main.BASE_URI);
    }

    @After
    public void tearDown() throws Exception {
        server.stop();
    }

    /**
     * Test to see that the message "Got it!" is sent in the response.
     */
    @Test
    public void testGetIt() {
        String responseMsg = target.path("myresource").request().get(String.class);
        assertEquals("Got it!", responseMsg);
    }
}