Why is this Simple JAX RS example not working?

Question

I am trying to get working a simple JAX RS example, but I am failing to do so.

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:jsp="http://java.sun.com/xml/ns/javaee/jsp" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>PLAYGROUND</display-name>
  <servlet-mapping>
    <servlet-name>playground.Rest</servlet-name>
    <url-pattern>/api/*</url-pattern>
  </servlet-mapping>
</web-app>

Rest.java

package playground;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Application;

public class Rest extends Application {
    @GET
    @Path("hello")
    public String helloworld() {
        return "Hello World!";
    }
}

Accessing http://localhost/{warcontext}/api/hello with the browser (GET) gives me 404 error status

It is probably something very silly but I can't figure out.

Using: JBoss EAP 6.1.0 (Java EE 6)

Solution 1

You need to extend javax.ws.rs.core.Application (it can remain empty) and annotate it with @ApplicationPath("/ide"), then create a JAX-RS resource, ie, a class with an @Path("/hello") annotation. In this class, you'll just need to have your JAX-RS Resource Method annotated with @GET.

@ApplicationPath("/ide")
public class Rest extends Application { }


@Path("/hello")
public class HelloResource {

  @GET
  @Path("hello")
  public String helloworld() {
      return "Hello World!";
  }
}

You can also take a look at this example: https://github.com/resteasy/Resteasy/tree/master/jaxrs/examples/oreilly-workbook/ex03_1

Solution 2

web.xml

<servlet>
    <servlet-name>RestServlet</servlet-name>
    <servlet-class>javax.ws.rs.core.Application</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>RestServlet</servlet-name>
    <url-pattern>/api/*</url-pattern>
</servlet-mapping>

Rest.java

public class Rest {
    @GET
    @Path("hello")
    public String helloworld() {
        return "Hello World!";
    }
}

---

If you need, you can add

YourApplication.java

package playground;
import javax.ws.rs.core.Application;
...
public class YourApplication extends Application {
    @Override
    public Set<Class<?>> getClasses()
    {
        Set<Class<?>> yourResources = new HashSet<Class<?>>();
        yourResources.add(InvoiceResource.class);
        return yourResources;
    }
}

Then

web.xml

<servlet>
    <servlet-name>RestServlet</servlet-name>
    <servlet-class>playground.YourApplication</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>RestServlet</servlet-name>
    <url-pattern>/api/*</url-pattern>
</servlet-mapping>

If you add @ApplicationPath("/api") for YouApplication, then web.xml shouldn't have servlet-mapping.