java - JAX-RS MessageBodyReader

我正在从提供者那里学习MessageBodyReader方法的工作方式。我看到该方法返回一个对象，但不确定如何从服务访问该对象。我可以解释一下如何从阅读器类返回对象吗？这将帮助我将阅读规则应用于所有DTO。提前致谢!
服务:

    @POST
    @Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON })
    @Path("/CreateAccount")
    @Consumes({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON })
    public Response createAccount(@Context HttpServletRequest req) {

        String a = "Reader success? ";//Would to see that string here!
        return Response.ok().build();
    }

提供者:

@Provider
public class readerClass implements MessageBodyReader<Object>
{

@Override
public boolean isReadable(Class<?> paramClass, Type paramType,
        Annotation[] paramArrayOfAnnotation, MediaType paramMediaType) {
    // TODO Auto-generated method stub
    return true;
}

@Override
public Object readFrom(Class<Object> paramClass, Type paramType,
        Annotation[] paramArrayOfAnnotation, MediaType paramMediaType,
        MultivaluedMap<String, String> paramMultivaluedMap,
        InputStream paramInputStream) throws IOException,
        WebApplicationException {
    // TODO Auto-generated method stub

    return "Successfully read from a providers reader method";
}

}

最佳答案

您误解了MessageBodyReader的用途，它用于以下目的:



范例:
如果您有使用xml/json以外的自定义格式的用例，则要提供自己的UnMarshaller，可以使用messagebody阅读器

    @Provider
    @Consumes("customformat")
    public class CustomUnmarshaller implements MessageBodyReader {

        @Override
        public boolean isReadable(Class aClass, Type type, Annotation[] annotations, MediaType mediaType) {
            return true;
        }


        @Override
        public Object readFrom(Class aClass, Type type, Annotation[] annotations, MediaType mediaType, MultivaluedMap multivaluedMap, InputStream inputStream) throws IOException, WebApplicationException {
            Object result = null;
            try {
                result = unmarshall(inputStream, aClass); // un marshall custom format to java object here
            } catch (Exception e) {
                e.printStackTrace();
            }

            return result;


}
}

在webservice中，您可以使用..

    @POST
    @Path("/CreateAccount")
    @Consumes("custom format")
    public Response createAccount(@Context HttpServletRequest req,Account acc) {

        saveAccount(acc); // here acc object is returned from your custom unmarshaller
        return Response.ok().build();
    }

更多信息:
Custom Marshalling/UnMarshalling Example，
Jersy Entity Providers Tutorial