Unable to get collection response from cxf rest web service

Question

I am trying to get java.util.List as response from cxf rest web service. I have tried with WebClient class's method postObjectGetCollection method but no luck. I am getting - org.apache.cxf.jaxrs.client.ClientWebApplicationException: .No message body reader has been found for class : interface java.util.Collection, ContentType : application/json.

Below are my client code-

String mediaType = "application/json";
        if (url != null) {
            List<DataTypeDTO>  resultdtos = new ArrayList<DataTypeDTO>();
            WebClient client = WebClient.create(url);
            client = client.accept(mediaType).type(mediaType).path(uri);
            resultdtos = (List<DataTypeDTO>)client.getCollection(DataTypeDTO.class); 
            System.out.println(resultdtos);
        }

Please help me out if i am missing any configuration or other things.

Answer 1

You need to provide the provider list while creating the webClient object in your rest client. You can use the below code to resolve your issue:

 final String url = "http://localhost:10227/someService";
        final String uri = "/manageXyz/fetchAllDataTypes";            
        final String mediaType = "application/json";
        Object response = null;
        List<Object> providers = new ArrayList<Object>();
        providers.add( new JacksonJaxbJsonProvider() );
        WebClient client = WebClient.create(url, providers);
        client = client.accept(mediaType).type(mediaType).path(uri);
        response = (List<Object>)client.post(oemUser, List.class); 

If you are using maven, you also need to provide below required jars to resolve maven dependency in your project:

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-jaxrs</artifactId>
    <version>1.5.4</version>
</dependency>
<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-core-asl</artifactId>
    <version>1.9.13</version>
</dependency>
<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-xc</artifactId>
    <version>1.9.13</version>
</dependency>