问题
I have an application (a servlet, but that's not very important) that downloads a set of files and parse them to extract information. Up to now, I did those operations in a loop : - fetching new file on the Internet - analyzing it.
A multi-threaded download-manager seems a better solution for this problem and I would like to implement it in the fastest way possible.
Some of the downloads are dependant from others (so, this set is partially ordered).
Mutli-threaded programming is hard and if I could find an API to do that I would be quite happy. I need to put a group of files (ordered) in a queue and get the first group of files that is completely downloaded.
Do you know of any library I could use to achieve that ?
Regards, Stéphane
回答1:
You could do something like:
BlockingQueue<Download> queue = new BlockingQueue<Download>();
ExecutorService pool = Executors.newFixedThreadPool(5);
Download obj = new Download(queue);
pool.execute(obj); //start download and place on queue once completed
Data data = queue.take(); //get completely downloaded item
You may have to use a different kind of queue if the speed of each download is not the same. BlockingQueue is first in first out I believe.
You may want to look into using a PriorityBlockingQueue which will order the Download objects according to their Comparable method. See the API here for more details.
Hope this helps.
来源:https://stackoverflow.com/questions/6480726/queueing-multiple-downloads-looking-for-a-producer-consumer-api