java JAXB在writeTo方法中写入OutputStream

Question

我一直在尝试在MessageBodyWriter接口的writeTo实现方法中直接将字符串写入OutputStream。我想在try-catch块中执行此操作，以便在捕获异常时发送消息。然而，当我调试程序时，我意识到字符串永远不会写入OutputStream（size=-1）

代码如下所示：

public void writeTo(final Object entityObject, final Class<?> aClass, final Type type,
                        final Annotation[] annotations, final MediaType mediaType,
                        final MultivaluedMap<String, Object> stringObjectMultivaluedMap,
                        final OutputStream outputStream) throws IOException, WebApplicationException {
   try{
     throw new JAXBException("error");
   }catch(JAXBException j){
     outputStream.write("HI".getBytes());
     outputStream.flush();
   }

Answer 1

新答案

您可以利用WebApplicationException，它可以从MessageBodyWriter中的writeTo方法抛出

public void writeTo(DataObject dataObject, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> multivaluedMap, OutputStream outputStream) throws IOException, WebApplicationException {
    try {
        throw new JAXBException("error");
    } catch(JAXBException e) {
        Response response = Response.status(Response.Status.INTERNAL_SERVER_ERROR)
                                     .entity("HI")
                                     .type("text/plain")
                                     .build();
        throw new WebApplicationException(response);
    }
}

原始答案

在我看来，最好从MessageBodyWriter抛出JAXBEException，然后创建ExceptionMapper来记录问题：

@Provider
public class JAXBExceptionMapper implements ExceptionMapper<JAXBException> {

    public Response toResponse(JAXBException e) {
        return Response.status(Response.Status.INTERNAL_SERVER_ERROR)
                       .entity(e.getMessage());
                       .type("text/plain").build();
    }

}

这将允许您返回指示出现问题的响应代码