404 error, Jersey 2.x on tomcat 8

问题:

I'm working on my first RESTful Api with Jersey 2.x and tomcat 8 but when I try to acceed to my Resources I keep getting a 404 errors.

this is my web.xml :

<?xml version="1.0" encoding="UTF-8"?>
<web-app 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    id="WebApp_ID" 
    version="3.1">

    <servlet>
        <servlet-name>com.pj.api.application.Application</servlet-name>
    </servlet>
    <servlet-mapping>
        <servlet-name>com.pj.api.application.Application</servlet-name>
        <url-pattern>/api/*</url-pattern>
    </servlet-mapping>
</web-app>

My Application class :

@ApplicationPath ("api")
public class Application extends ResourceConfig {

    public Application () {
        packages ("com.pj.api.resources");
    }   
}

My Resources class :

@Path ("value=/users")
public class UserResources extends ResourcesImpl {

    private UserDao user = new UserDao ();

    @Override
    public List<Data> getList () {
        return user.getList ();
    }

    @GET
    @Path ("value=/test")
    public String Test () {
        return "{'a':'hey'}";
    }

    @Override
    public Data get (String id) {
        return user.get (id);
    }

    @Override
    public void post (Data data) {
        user.post (data);
    }

    @Override
    public void put (Data data) {
        user.put (data);
    }

    @Override
    public void delete(Data data) {
        user.delete (data);
    }
}

When deploying the project on Tomcat, and acceeding to the Service through the URL : http://localhost:8080/PJ/api/users/test it gives me a 404 error and Cannot cast org.glassfish.jersey.servlet.init.JerseyServletContainerInitializer to javax.servlet.ServletContainerInitializer

p.s : I do NOT use Maven

What could be the problem here ? Thank you.

回答1:

This certainly looks like a classpath issue. Does your server runtime include some default Jax-rs libraries? I faced a similar issue when trying to deploy my app built on Jersey 2.4 on a server that included jax-rs 1.1 libraries, so I had to rebuild my app on Jersey 1.18. Check your server runtime in Eclipse for any existing libraries

回答2:

Your app differs a lot from mine. I suggest you to take a look at a simple hello world example that you can find here.

As you can see a simple service is:

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

    @GET
    @Path("/{param}")
    public Response getMsg(@PathParam("param") String msg) {

         String output = "Jersey say : " + msg;
         return Response.status(200).entity(output).build();
    }
 }

the web.xml should look like:

<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>Restful Web Application</display-name>

<servlet>
    <servlet-name>jersey-serlvet</servlet-name>
    <servlet-class>
                 com.sun.jersey.spi.container.servlet.ServletContainer
            </servlet-class>
    <init-param>
         <param-name>com.sun.jersey.config.property.packages</param-name>
         <param-value>com.mkyong.rest</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>jersey-serlvet</servlet-name>
    <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

Web request from projectURL/rest/hello/ will match to HelloWorldService through @Path("/hello") and the {any values} from projectURL/rest/hello/{any values} will match to parameter annotated with @PathParam.

The URL is http://localhost:8080/<your_project>/rest/hello/Mehdi

You can use this base example as a root base and adapt it to your needs.

Hope to help