多线程并发

JUnit推荐了一个多线程的断言方法(需要根据自己的需求复制或修改):

public static void assertConcurrent(final String message, final List<? extends Runnable> runnables, final int maxTimeoutSeconds) throws InterruptedException {
    final int numThreads = runnables.size();
    final List<Throwable> exceptions = Collections.synchronizedList(new ArrayList<Throwable>());
    final ExecutorService threadPool = Executors.newFixedThreadPool(numThreads);
    try {
        final CountDownLatch allExecutorThreadsReady = new CountDownLatch(numThreads);
        final CountDownLatch afterInitBlocker = new CountDownLatch(1);
        final CountDownLatch allDone = new CountDownLatch(numThreads);
        for (final Runnable submittedTestRunnable : runnables) {
            threadPool.submit(new Runnable() {
                public void run() {
                    allExecutorThreadsReady.countDown();
                    try {
                        afterInitBlocker.await();
            submittedTestRunnable.run();
                    } catch (final Throwable e) {
                        exceptions.add(e);
                    } finally {
                        allDone.countDown();
                    }
                }
            });
        }
        // wait until all threads are ready
        assertTrue("Timeout initializing threads! Perform long lasting initializations before passing runnables to assertConcurrent", allExecutorThreadsReady.await(runnables.size() * 10, TimeUnit.MILLISECONDS));
        // start all test runners
        afterInitBlocker.countDown();
        assertTrue(message +" timeout! More than" + maxTimeoutSeconds + "seconds", allDone.await(maxTimeoutSeconds, TimeUnit.SECONDS));
    } finally {
        threadPool.shutdownNow();
    }
    assertTrue(message + "failed with exception(s)" + exceptions, exceptions.isEmpty());
}