CODEWITHSUNDEEP
javarest
tin_tin
tin_tin

Reputation: 488

returning List<String> from a Rest webservice

Iam learning REST webservice. I have written a very basic code to return a List from the webservice. below is code snippet 

@Path("hello")
public class Hello {


    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public List<String> greeting() {

        List<String> greeting = new ArrayList<>();
        greeting.add("Hello World");
        greeting.add("How are you");
        greeting.add("Hope you are doing good");
        greeting.add("Hey WhatsApp");
        greeting.add("Take care");
        greeting.add("Perform well");


        return greeting;
    }

}

the messagebodywriter implementation is below 

@Provider
@Produces(MediaType.TEXT_PLAIN)
public class ListMessageBodyWriter implements MessageBodyWriter<List<String>>{

    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {        
        System.out.println("here in the isWriteable");

        return type == List.class;
    }

    @Override
    public void writeTo(List<String> t, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType,
            MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream)
            throws IOException, WebApplicationException {

        System.out.println("here in the writeTo");
        System.out.println("t="+t);
        System.out.println("size of t "+t.size());

        Writer writer = new PrintWriter(entityStream);
        writer.write("list of string will be returned later");
        writer.flush();
        writer.close();

    }

But when i run the code i still get the same error as below

MessageBodyWriter not found for media type=text/plain, type=class java.util.ArrayList, genericType=java.util.List.

Why iam getting the same error despite implementing the messagebodywriter?

Upvotes: 0

Views: 186

Answers (1)

tin_tin
tin_tin

Reputation: 488

@Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {        
        System.out.println("here in the isWriteable");

        return type == List.class;
    }

changing the return type == List.class; to

return type == ArrayList.class; solved the error.

Upvotes: 1

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