使用您自己的Future实现：
public class BazComputationFuture implements Future<Baz>, BazComputationSink { private volatile Baz result = null; private volatile boolean cancelled = false; private final CountDownLatch countDownLatch; public BazComputationFuture() { countDownLatch = new CountDownLatch(1); } @Override public boolean cancel(final boolean mayInterruptIfRunning) { if (isDone()) { return false; } else { countDownLatch.countDown(); cancelled = true; return !isDone(); } } @Override public Baz get() throws InterruptedException, ExecutionException { countDownLatch.await(); return result; } @Override public Baz get(final long timeout, final TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException { countDownLatch.await(timeout, unit); return result; } @Override public boolean isCancelled() { return cancelled; } @Override public boolean isDone() { return countDownLatch.getCount() == 0; } public void onBazResult(final Baz result) { this.result = result; countDownLatch.countDown(); }}public Future<Baz> doSomething(Foo fooArg, Bar barArg) { BazComputationFuture future = new BazComputationFuture(); doSomethingAsync(fooArg, barArg, future); return future;}public Baz doSomethingAndBlock(Foo fooArg, Bar barArg) { return doSomething(fooArg, barArg).get();}该解决方案在内部创建一个CountDownLatch，一旦收到回调，该计数器将被清除。如果用户调用get，则使用CountDownLatch阻止调用线程，直到计算完成并调用onBazResult回调。CountDownLatch将确保如果回调在调用get（）之前发生，则get（）方法将立即返回结果。
