找不到媒体类型= Application / json，glassfish的MessageBodyWriter

Question

I'm using JAX-RS to create simple restful json my first method work fine but when I add 2nd to get all vendorNOS"ID" method I have this exception when I view the in browser I also debug the Restful service and it work fine it gell all vendorNOS"ID"

my output from vendorFacadeBean is {1,2,3,4,5,6,11,13}

HTTP Status 500 - Internal Server Error

type Exception report

messageInternal Server Error

descriptionThe server encountered an internal error that prevented it from fulfilling this request.

exception

    javax.servlet.ServletException: org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyWriter not found for media type=Application/json, type=class java.util.Vector, genericType=java.util.List<java.lang.Integer>.
    root cause

    org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyWriter not found for media type=Application/json, type=class java.util.Vector, genericType=java.util.List<java.lang.Integer>.
    note The full stack traces of the exception and its root causes are available in the GlassFish Server Open Source Edition 4.0 logs.

    GlassFish Server Open Source Edition 4.0

java source code

package resources;

import case2dtos.VendorEJBDTO;
import case2ejbs.VendorFacadeBean;
import java.util.List;
import javax.ejb.EJB;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.PathParam;
import javax.ws.rs.Consumes;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.GET;
import javax.ws.rs.Produces;
import javax.enterprise.context.RequestScoped;

/**
 * REST Web Service
 *
 * @author abdallaelnajjar
 */
@Path("vendors")
@RequestScoped
public class VendorsResource {
    @EJB
    private VendorFacadeBean vendorFacadeBean;

    @Context
    private UriInfo context;

    /**
     * Creates a new instance of VendorsResource
     */
    public VendorsResource() {
    }

    /**
     * Retrieves representation of an instance of resources.VendorsResource
     * @return an instance of java.lang.String
     */
    @GET
    @Path("getAVendor/{vendorno}")
    @Produces("Application/json")
    public VendorEJBDTO getAVendor(@PathParam("vendorno")int vendorno)
    {
        return vendorFacadeBean.getVendorInfo(vendorno);
    }

    /**
     * Retrieves representation of an instance of resources.VendorsResource
     * @return an instance of java.lang.String
     */
    @GET
    @Path("getVendornos")
    @Produces("Application/json")
    public List<Integer> getVendornos()
    {
        List<Integer> vendornosList = null;
        try 
        {
         vendornosList =  vendorFacadeBean.getVendorsnos();
        }
        catch(Exception e)
        {
            System.out.println(e.getMessage());
        }

        return vendornosList;
    }
}

Answer 1

Use genson ( https://code.google.com/p/genson/downloads/list ) jar and add this to class path. This will convert any object to json format. You get this error because you do not have a json provider. And it is better to return object rather than toString().

As well as you can use JAXB jar which comes with jersey bundle. This will support both XML and JSON. You can find the jar inside /ext folder of jersey distribution.

Answer 2

I solved it by adding the following dependency.

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-moxy</artifactId>
    <version>2.17</version>
</dependency>

I am using jersey-spring3 , jersey 2 and spring4 .

Answer 3

The problem seems with List<Integer> that you are returning from second method.

Are you seeing error like the following?

javax.ws.rs.WebApplicationException: com.sun.jersey.api.MessageException: A message body writer for Java class java.util.ArrayList, and Java type class java.util.ArrayList, and MIME media type application/xml was not found

Please refer to GenericEntity . Moreover this seems duplicate .