spring webflux Flux<DataBuffer> 转换为 InputStream

Question

我目前正在研究 Spring WebFlux。我正在尝试使用 Spring WebFlux 上传大文件（70mo）。

我的控制器

@RequestMapping(method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
public Flux<String> uploadHandler(@RequestBody Flux<Part> fluxParts, @RequestParam(value = "categoryType") String categoryType, @PathVariable(value = "traceabilityReportUuid") String traceabilityUuid) {
    return documentHandler.upload(fluxParts, UUID.fromString(traceabilityUuid), categoryType);
}

我的服务

public Flux<String> upload(Flux<Part> fluxParts, UUID traceabilityUuid, String categoryType) {

    return fluxParts
            .filter(part -> part instanceof FilePart)
            .ofType(FilePart.class)
            .flatMap(p -> this.upload(p, traceabilityUuid, categoryType));


}


private Mono<String> upload(FilePart filePart, UUID traceabilityUuid, String categoryType) {

    return filePart.content().collect(InputStreamCollector::new, (t, dataBuffer) -> t.collectInputStream(dataBuffer.asInputStream()))
            .flatMap(inputStreamCollector -> {
                upload(traceabilityUuid, inputStreamCollector.getInputStream(), filePart.filename(), categoryType);

                return Mono.just("OK");
            });
}

我的收藏家

public class InputStreamCollector {

    private InputStream is;

    public void collectInputStream(InputStream is) {
        if (this.is == null) this.is = is;
        this.is = new SequenceInputStream(this.is, is);
    }

    public InputStream getInputStream() {
        return this.is;
    }
}

最后，我通过这种方式检索完整的输入流：inputStreamCollector.getInputStream()并传递给我的对象。

我使用这个对象来发送到存储桶 S3。

但在发送到 S3 之前，我必须将其转换为文件（使用 apache 工具），我遇到了 stackoverflow 异常。

java.lang.StackOverflowError: null
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)
at java.base/java.io.SequenceInputStream.read(SequenceInputStream.java:156)

它适用于小文件（7mo ..）

您有办法解决我的问题吗？

Answer 1

最后我找到了解决方案！

https://github.com/entzik/reactive-spring-boot-examples/blob/master/src/main/java/com/thekirschners/springbootsamples/reactiveupload/ReactiveUploadResource.java

我调整了代码以返回 InputStream 并且它可以很好地处理大文件;-)