受到T.Nurkiewicz的“用RxJava进行反应式编程”的启发,我尝试将它应用到我正在处理的项目中,这是我面临的问题。RxJava:OnErrorFailedException。识别正确的原因
我有一个Rest端点,它接受一个输入流和一个用户名,并且为更新的用户名返回一个链接或返回一个错误的请求错误。以下是我想实现这个使用RxJava:
@PUT
@Path("{username}")
public Response updateCredential(@PathParam("username") final String username, InputStream stream) {
CredentialCandidate candidate = new CredentialCandidate();
Observable.just(repository.getByUsername(username))
.subscribe(
credential -> {
serializeCandidate(candidate, stream);
try {
repository.updateCredential(build(credential, candidate));
} catch (Exception e) {
String msg = "Failed to update credential +\""+username+"\": "+e.getMessage();
throw new BadRequestException(msg, Response.status(Response.Status.BAD_REQUEST).build());
}
},
ex -> {
String msg = "Couldn't update credential \""+username+"\""
+ ". A credential with such username doesn't exist: " + ex.getMessage();
logger.error(msg);
throw new BadRequestException(msg, Response.status(Response.Status.BAD_REQUEST).build());
});//if the Observable completes without exceptions we have a success case
Map<String, String> map = new HashMap<>();
map.put("path", "credential/" + username);
return Response.ok(getJsonRepr("link", uriGenerator.apply(appsUriBuilder, map).toASCIIString())).build();
}
我的问题是在该行11(onNext
方法的catch子句)。这是日志输出,迅速将展示发生了什么:
19:23:50.472 [http-listener(4)] ERROR com.vgorcinschi.rimmanew.rest.services.CredentialResourceService - Couldn't update credential "admin". A credential with such username doesn't exist: Failed to update credential +"admin": Password too weak!
所以在onNext
方法抛出的异常用于上游和结束行动的onError
方法!显然this works as designed,但我很困惑,我可以如何返回错误请求错误的正确原因。毕竟在我的测试用例中,存储库找到了用户的凭证,但是正确的错误是建议的密码太弱。这是产生错误的helper方法:
private Credential build(Credential credential, CredentialCandidate candidate) {
if(!isOkPsswd.test(candidate.getPassword())){
throw new BadRequestException("Password too weak!", Response.status(Response.Status.BAD_REQUEST).build());
}
...
}
我仍然相当新的反应式编程,所以我意识到我可能会丢失的东西是显而易见的。浏览本书并没有让我得到答案,所以我会很感激任何帮助。
以防万一,这是完整的堆栈跟踪:
updateCredentialTest(com.vgorcinschi.rimmanew.services.CredentialResourceServiceTest) Time elapsed: 0.798 sec <<< ERROR!
rx.exceptions.OnErrorFailedException: Error occurred when trying to propagate error to Observer.onError
at com.vgorcinschi.rimmanew.rest.services.CredentialResourceService.lambda$updateCredential$9(CredentialResourceService.java:245)
at rx.internal.util.ActionSubscriber.onNext(ActionSubscriber.java:39)
at rx.observers.SafeSubscriber.onNext(SafeSubscriber.java:134)
at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276)
at rx.Subscriber.setProducer(Subscriber.java:209)
at rx.Subscriber.setProducer(Subscriber.java:205)
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138)
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129)
at rx.Observable.subscribe(Observable.java:10238)
at rx.Observable.subscribe(Observable.java:10205)
at rx.Observable.subscribe(Observable.java:10045)
at com.vgorcinschi.rimmanew.rest.services.CredentialResourceService.updateCredential(CredentialResourceService.java:238)
at com.vgorcinschi.rimmanew.services.CredentialResourceServiceTest.updateCredentialTest(CredentialResourceServiceTest.java:140)