在JAX-RS 2.0客户端库中处理自定义错误响应

Question

{
    "code": 400,
    "message": "This is a message which describes why there was a code 400."
} 

然而，JAX-RS2.0客户机正在将400状态重新映射为一般的状态，因此我丢失了良好的错误消息。它正确地将其映射到一个BadRequestException，但带有一个通用的“HTTP 400 Bad Request”消息。

javax.ws.rs.BadRequestException: HTTP 400 Bad Request
    at org.glassfish.jersey.client.JerseyInvocation.convertToException(JerseyInvocation.java:908)
    at org.glassfish.jersey.client.JerseyInvocation.translate(JerseyInvocation.java:770)
    at org.glassfish.jersey.client.JerseyInvocation.access$500(JerseyInvocation.java:90)
    at org.glassfish.jersey.client.JerseyInvocation$2.call(JerseyInvocation.java:671)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:424)
    at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:667)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:396)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:296)

是否有某种类型的拦截器或自定义错误处理程序可以被注入，以便我访问真正的错误消息。我一直在查看文档，但看不到任何方法。

我现在正在使用泽西，但我用CXF尝试了这个，得到了同样的结果。下面是代码的样子。

Client client = ClientBuilder.newClient().register(JacksonFeature.class).register(GzipInterceptor.class);
WebTarget target = client.target("https://somesite.com").path("/api/test");
Invocation.Builder builder = target.request()
                                   .header("some_header", value)
                                   .accept(MediaType.APPLICATION_JSON_TYPE)
                                   .acceptEncoding("gzip");
MyEntity entity = builder.get(MyEntity.class);

下面是我的过滤器类：

@Provider
public class ErrorResponseFilter implements ClientResponseFilter {

    private static ObjectMapper _MAPPER = new ObjectMapper();

    @Override
    public void filter(ClientRequestContext requestContext, ClientResponseContext responseContext) throws IOException {
        // for non-200 response, deal with the custom error messages
        if (responseContext.getStatus() != Response.Status.OK.getStatusCode()) {
            if (responseContext.hasEntity()) {
                // get the "real" error message
                ErrorResponse error = _MAPPER.readValue(responseContext.getEntityStream(), ErrorResponse.class);
                String message = error.getMessage();

                Response.Status status = Response.Status.fromStatusCode(responseContext.getStatus());
                WebApplicationException webAppException;
                switch (status) {
                    case BAD_REQUEST:
                        webAppException = new BadRequestException(message);
                        break;
                    case UNAUTHORIZED:
                        webAppException = new NotAuthorizedException(message);
                        break;
                    case FORBIDDEN:
                        webAppException = new ForbiddenException(message);
                        break;
                    case NOT_FOUND:
                        webAppException = new NotFoundException(message);
                        break;
                    case METHOD_NOT_ALLOWED:
                        webAppException = new NotAllowedException(message);
                        break;
                    case NOT_ACCEPTABLE:
                        webAppException = new NotAcceptableException(message);
                        break;
                    case UNSUPPORTED_MEDIA_TYPE:
                        webAppException = new NotSupportedException(message);
                        break;
                    case INTERNAL_SERVER_ERROR:
                        webAppException = new InternalServerErrorException(message);
                        break;
                    case SERVICE_UNAVAILABLE:
                        webAppException = new ServiceUnavailableException(message);
                        break;
                    default:
                        webAppException = new WebApplicationException(message);
                }

                throw webAppException;
            }
        }
    }
}

Answer 1

我相信你想做这样的事情：

Response response = builder.get( Response.class );
if ( response.getStatusCode() != Response.Status.OK.getStatusCode() ) {
    System.out.println( response.getStatusType() );
    return null;
}

return response.readEntity( MyEntity.class );

您可以尝试的另一件事情是（因为我不知道这个API把东西放在哪里--例如，在头部或实体中或什么）：

Response response = builder.get( Response.class );
if ( response.getStatusCode() != Response.Status.OK.getStatusCode() ) {
    // if they put the custom error stuff in the entity
    System.out.println( response.readEntity( String.class ) );
    return null;
}

return response.readEntity( MyEntity.class );

如果您希望将REST响应代码映射到Java exception，可以添加一个客户机过滤器来实现这一点：

class ClientResponseLoggingFilter implements ClientResponseFilter {

    @Override
    public void filter(final ClientRequestContext reqCtx,
                       final ClientResponseContext resCtx) throws IOException {

        if ( resCtx.getStatus() == Response.Status.BAD_REQUEST.getStatusCode() ) {
            throw new MyClientException( resCtx.getStatusInfo() );
        }

        ...