英文:
How to convert a Flux<DataBuffer> into a StreamingResponseBody in a Spring Controller
问题
我在我的Spring Controller中有一个DataBuffer的Flux，并希望将其附加到StreamingResponseBody作为流。我已经阅读了许多类似方法的答案，但没有完全符合这个情况。我不想将整个文件加载到内存中，我想要流式传输。
@GetMapping(value="/attachment")public ResponseEntity<StreamingResponseBody> get(@PathVariable long attachmentId) {Flux<DataBuffer> dataBuffer = this.myService.getFile(attachmentId);StreamingResponseBody stream = out -> {// 在这里要做什么？}return ResponseEntity.ok().contentType(MediaType.APPLICATION_OCTET_STREAM).body(stream);}
EDIT: myService.getFile()
public Flux<DataBuffer> getFile(long attachmentId) {return this.webClient.get().uri("https://{host}/attachments/{attachmentId}", host, attachmentId).attributes(clientRegistrationId("attachmentClient")).accept(MediaType.ALL).exchangeToFlux(clientResponse -> clientResponse.bodyToFlux(DataBuffer.class));}
希望这有所帮助。
英文:
I have a Flux of DataBuffer in my Spring Controller and I want to attach it to the StreamingResponseBody as a stream. I have read many answers for similar approaches, but nothing quite matches this. I do not want to load the entire file in memory. I want it streamed.
@GetMapping(value="/attachment")public ResponseEntity<StreamingResponseBody> get(@PathVariable long attachmentId) {Flux<DataBuffer> dataBuffer = this.myService.getFile(attachmentId);StreamingResponseBody stream = out -> {// what do do here?}return ResponseEntity.ok().contentType(MediaType.APPLICATION_OCTET_STREAM).body(stream);}}
EDIT: myService.getFile()
public Flux<DataBuffer> gteFile(long attachmentId) {return this.webClient.get().uri("https://{host}/attachments/{attachmentId}", host, attachmentId).attributes(clientRegistrationId("attachmentClient")).accept(MediaType.ALL).exchangeToFlux(clientResponse -> clientResponse.bodyToFlux(DataBuffer.class));}
答案1
得分: 1
如果您使用WebFlux，就不需要返回StreamingResponseBody，可以直接返回Flux<DataBuffer>，这样它就会进行流式传输并且是非阻塞的。
如果您想要添加一些标头/自定义您的响应，那么可以返回Mono<ResponseEntity<Flux<DataBuffer>>>：
@GetMapping("/attachment/{attachmentId}")public Mono<ResponseEntity<Flux<DataBuffer>>> get(@PathVariable long attachmentId) {Flux<DataBuffer> dataBuffers = this.myService.getFile(attachmentId);ContentDisposition contentDisposition = ContentDisposition.inline().filename("example.txt").build();HttpHeaders headers = new HttpHeaders();headers.setContentDisposition(contentDisposition);return Mono.just(ResponseEntity.ok().headers(headers).contentType(MediaType.APPLICATION_OCTET_STREAM).body(dataBuffers));}
如果您想要使用StreamingResponseBody（这意味着您正在使用阻塞的Spring MVC在Web层），那么您可以执行以下操作：
StreamingResponseBody stream = outputStream ->Mono.create(sink -> DataBufferUtils.write(dataBuffers, outputStream).subscribe(DataBufferUtils::release, sink::error, sink::success)).block();
然后从您的控制器返回它。
英文:
If you're using WebFlux there's no need to return StreamingResponseBody, you can just return Flux<DataBuffer> directly, so it will be streaming and also non-blocking.
If you want to add some headers/customize your response, the you can return Mono<ResponseEntity<Flux<DataBuffer>>> :
<!-- language: java -->
@GetMapping("/attachment/{attachmentId}")
public Mono<ResponseEntity<Flux<DataBuffer>>> get(@PathVariable long attachmentId) {
Flux<DataBuffer> dataBuffers = this.myService.getFile(attachmentId);ContentDisposition contentDisposition = ContentDisposition.inline().filename("example.txt").build();HttpHeaders headers = new HttpHeaders();headers.setContentDisposition(contentDisposition);return Mono.just(ResponseEntity.ok().headers(headers).contentType(MediaType.APPLICATION_OCTET_STREAM).body(dataBuffers));}
If you want to use StreamingResponseBody (which means you're using blocking Spring MVC on web-layer), then you can do the following:
<!-- language: java -->
StreamingResponseBody stream = outputStream ->Mono.create(sink -> DataBufferUtils.write(dataBuffers, outputStream).subscribe(DataBufferUtils::release, sink::error, sink::success)).block();
and then return it from your controller
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