将RxJava排放写入文本文件的有效方法？

Question

What is the most effective way to write an Observable<T> of items into a text file, where a line is written for each emission? I am using a try-with-resources setup below with a CountDownLatch , but it definitely feels like an anti-pattern due to the blocking. There is also a strong possibility of interruptions and early unsubscriptions throwing errors.

 private void saveToCSV(String url) {

        CountDownLatch latch = new CountDownLatch(1);

        File outputFile = new File(url);

        try(BufferedWriter writer = new BufferedWriter(new FileWriter(outputFile))) {

            writer.write(ReportItem.getHeaders() + "\r\n");

            reportItems.forDate(dt)
                    .map(ReportItem::toCSVLine).map(s -> s.concat("\r\n"))
                    .subscribe(Checked.a1(writer::write), Throwable::printStackTrace, latch::countDown);

            latch.await(); 

        } catch (Exception e) {
            e.printStackTrace();
        }
}

Answer 1

After a second thought, Observable.using() is perhaps not the best candidate here. I would try simply something like this (with finallyDo() instead):

private void saveToCSV(String url) {
    BufferedWriter writer = getBufferedWriter(url);
    writer.write(ReportItem.getHeaders() + "\r\n");
    reportItems.forDate(dt)
               .map(ReportItem::toCSVLine).map(s -> s.concat("\r\n"))
               .finallyDo(() -> close(writer))
               .subscribe(Checked.a1(writer::write), Throwable::printStackTrace);
}

private void close(BufferedWriter writer) {
    try {
        writer.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

private BufferedWriter getBufferedWriter(String url) {
    try {
        File outputFile = new File(url);
        return new BufferedWriter(new FileWriter(outputFile));
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}