在Retrofit 1 时，会在onError中返回并抛出HttpException，但是在2中，不会再回调onError了，而是会在onNext中，这个任务就需要客户端自己处理。 https://futurestud.io/tutorials/retrofit-2-simple-error-handling 参考如下： Error Handler in Action etrofit 2 has a different concept of handling "successful" requests than Retrofit 1. In Retrofit 2, all requests that can be executed (sent to the API) and for which you’re receiving a response are seen as "successful". That means, for these requests the onResponse callback is fired and you need to manually check whether the request is actual successful (status 200-299) or erroneous (status 400-599). If the request finished successfully, we can use the response object and do whatever we wanted. In case the error actually failed (remember, status 400-599), we want to show the user appropriate information about the issue. [crayon-592f9a65d7dfd546281355/] As you can see, we use the ErrorUtils class to parse the error body and get an APIError object. Use this object and the contained information to show a meaningful message instead of a generic error message.