实现效果:
启动一个任务,然后等待任务的计算结果同时设定一个超时时间,如果等待时间超出预设定的超时时间,则中止任务。
代码实现:
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* 启动一个任务,然后等待任务的计算结果,如果等待时间超出预设定的超时时间,则中止任务。
*
* @author Chen Feng
*/
public class TaskTimeoutDemo {
public static void main(String[] args) {
System.out.println("Start ...");
ExecutorService exec = Executors.newCachedThreadPool();
testTask(exec, 15); // 任务成功结束后等待计算结果,不需要等到15秒
testTask(exec, 5); // 只等待5秒,任务还没结束,所以将任务中止
exec.shutdown();
System.out.println("End!");
}
public static void testTask(ExecutorService exec, int timeout) {
MyTask task = new MyTask();
Future<Boolean> future = exec.submit(task);
Boolean taskResult = null;
String failReason = null;
try {
// 等待计算结果,最长等待timeout秒,timeout秒后中止任务
taskResult = future.get(timeout, TimeUnit.SECONDS);
} catch (InterruptedException e) {
failReason = "主线程在等待计算结果时被中断!";
} catch (ExecutionException e) {
failReason = "主线程等待计算结果,但计算抛出异常!";
} catch (TimeoutException e) {
failReason = "主线程等待计算结果超时,因此中断任务线程!";
exec.shutdownNow();
}
System.out.println("\ntaskResult : " + taskResult);
System.out.println("failReason : " + failReason);
}
}
class MyTask implements Callable<Boolean> {
@Override
public Boolean call() throws Exception {
// 总计耗时约10秒
for (int i = 0; i < 100L; i++) {
Thread.sleep(100); // 睡眠0.1秒
System.out.print('-');
}
return Boolean.TRUE;
}
}
运行结果:
Start ...
----------------------------------------------------------------------------------------------------
taskResult : true
failReason : null
---------------------------------------------
taskResult : null
failReason : 主线程等待计算结果超时,因此中断任务线程!
End!