一:
submit()方法,可以提供Future < T > 类型的返回值。
executor()方法,无返回值。
execute无返回值
public void execute(Runnable command) {
if (command == null)
throw new NullPointerException();//抛掉异常
int c = ctl.get();
if (workerCountOf(c) < corePoolSize) {
if (addWorker(command, true))
return;
c = ctl.get();
}
if (isRunning(c) && workQueue.offer(command)) {
int recheck = ctl.get();
if (! isRunning(recheck) && remove(command))
reject(command);
else if (workerCountOf(recheck) == 0)
addWorker(null, false);
}
else if (!addWorker(command, false))
reject(command);
}
submit有Future返回值 :
/**
* @throws RejectedExecutionException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
public Future<?> submit(Runnable task) {
if (task == null) throw new NullPointerException();
RunnableFuture<Void> ftask = newTaskFor(task, null);
execute(ftask);
return ftask;
}
/**
* @throws RejectedExecutionException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
public <T> Future<T> submit(Runnable task, T result) {
if (task == null) throw new NullPointerException();
RunnableFuture<T> ftask = newTaskFor(task, result);
execute(ftask);
return ftask;
}
/**
* @throws RejectedExecutionException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
public <T> Future<T> submit(Callable<T> task) {
if (task == null) throw new NullPointerException();
RunnableFuture<T> ftask = newTaskFor(task);
execute(ftask);
return ftask;
}
二:
excute方法会抛出异常。
sumbit方法不会抛出异常。除非你调用Future.get()。
三:
excute入参Runnable
submit入参可以为Callable
public interface Executor {
void execute(Runnable command);
}
public interface ExecutorService extends Executor {
...
<T> Future<T> submit(Callable<T> task);
<T> Future<T> submit(Runnable task, T result);
Future<?> submit(Runnable task);
...
}