Question

I start one thread to download contents from the internet, at one time, the thread is downloading one file, and then i want it stop and begin to download another file, what should i do? should i count on the concurrency mechanism in java?

Answer 1

You can start your thread using a single-thread executor, then when you kill it (gracefully I hope) and start a new one it will ensure that it’s using the same thread.

// Suppose you have a DownloadFile class that implements Runnable
DownloadFile task1 = new DownloadFile();

...

ExecutorService exec = Executors.newSingleThreadExecutor();

Future<Boolean> future = exec.submit( task1, Boolean.TRUE );

...

// Cancel the task
future.cancel();

// Give the executor another task
DownloadFile task2 = new DownloadFile();
...
exec.submit( task2, Boolean.TRUE );

Other useful docs:

• Future
• ExecutorService