JAX-RS using Jersey and Maven on Tomcat 7

Mon, Apr 8, 2013

Create a basic Maven project called RestTest with no archetype in Eclipse. Add the dynamic web project facet to your project and let Eclipse generate a default web.xml file for you. Then add the following Jersey dependencies to your pom.xml:

<dependencies>
  <dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-servlet</artifactId>
    <version>1.17.1</version>
  </dependency>
  <dependency>
    <groupId>com.sun.jersey</groupId>
    <artifactId>jersey-json</artifactId>
    <version>1.17.1</version>
  </dependency>
</dependencies>

And the following servlet and servlet mapping to your web.xml:

<servlet>
  <servlet-name>JAX-RS Servlet</servlet-name>
  <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
  <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
  <servlet-name>JAX-RS Servlet</servlet-name>
  <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

Now lets create a very basic JAX-RS service:

import java.util.ArrayList;
import java.util.List;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
@Path("/")
public class CatService {
  @Path("cats")
  @GET
  @Produces("application/json; charset=UTF-8")
  public List<Cat> getCats() {
    final Cat cat1 = new Cat("Julien", 2);
    final Cat cat2 = new Cat("Tom", 6);
    final List<Cat> cats = new ArrayList<Cat>();
    cats.add(cat1);
    cats.add(cat2);
    return cats;
  }
}

And a small model class:

public class Cat {
  public String name;
  public int age;
  public Cat(final String name, final int age) {
    this.name = name;
    this.age = age;
  }
}

Now add the application to Tomcat and start the server. On startup you should see something like this in your console:

Apr 08, 2013 4:26:28 PM com.sun.jersey.api.core.servlet.WebAppResourceConfig init
INFO: Scanning for root resource and provider classes in the Web app resource paths:
  /WEB-INF/lib
  /WEB-INF/classes
Apr 08, 2013 4:26:28 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Root resource classes found:
  class CatService
Apr 08, 2013 4:26:28 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Provider classes found:
  class org.codehaus.jackson.jaxrs.JacksonJaxbJsonProvider
  class org.codehaus.jackson.jaxrs.JsonMappingExceptionMapper
  class org.codehaus.jackson.jaxrs.JsonParseExceptionMapper
  class org.codehaus.jackson.jaxrs.JacksonJsonProvider
Apr 08, 2013 4:26:28 PM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate
INFO: Initiating Jersey application, version 'Jersey: 1.17.1 02/28/2013 12:47 PM'

Jersey automatically picked up your service and also discovered a JSON provider, that will help us convert objects to JSON . Try it yourself and call http://localhost:8080/RestTest/rest/cats in your browser. You should get the following:

[{"name":"Julien","age":2},{"name":"Tom","age":6}]