如何将下载的文件返回为 DataBuffer

Question

我正在下载如下文件：

private File downloadAndReturnFile(String fileId, String destination) {
    log.info("Downloading file.. " + fileId);
    Path path = Paths.get(destination);
    Flux<DataBuffer> dataBuffer = webClient.get().uri("/the/download/uri/" + fileId + "").retrieve()
            .bodyToFlux(DataBuffer.class)
            .doOnComplete(() -> log.info("{}", fileId + " - File downloaded successfully"));
    
    //DataBufferUtils.write(dataBuffer, path, StandardOpenOption.CREATE).share().block();
    
    return ???? // What should I do here to return above DataBuffer as file? 
}

如何将 dataBuffer 作为文件返回？或者，如何将此 dataBuffer 转换为 File 对象？

Answer 1

如果有人在寻找完整的代码。只是充分分享 Tonny 的解决方案。

private File downloadAndReturnFile(String fileId, String destination) throws FileNotFoundException {
            log.info("Downloading file.. " + fileId);
            Flux<DataBuffer> dataBuffer = webClient.get().uri("/the/download/uri/" + fileId + "").retrieve()
                    .bodyToFlux(DataBuffer.class)
                    .doOnComplete(() -> log.info("{}", fileId + " - File downloaded successfully"));
            Path path = Paths.get(destination);
            DataBufferUtils.write(dataBuffer, path, StandardOpenOption.CREATE).share().block();
            return path.toFile();
        }

Answer 2

您可以使用DataBufferUtils.write method。为此，您应该

1. 实例化一个File 对象（可能使用fileId 和destination），这也是您想要的返回值
2. 从File 对象创建OutputStream 或Path 或Channels 对象
3. 调用DataBufferUtils.write(dataBuffer, ....).share().block()将DataBuffer写入文件

即。 （省略所有抛出的异常），

...
File file = new File(destination, fileId);
Path path = file.toPath();
DataBufferUtils.write(dataBuffer, path, StandardOpenOption.CREATE).share().block();
return file;

或者，

...
Path path = Paths.get(destination);
DataBufferUtils.write(dataBuffer, path, StandardOpenOption.CREATE).share().block();
return path.toFile();