我很好的JavaScript承诺。所以我想试用Java Futures(仍然停留在Java 7中)。但是这些Java期货对我来说没有意义。下面是一个修整和改进的journaldev版本:Java未来:有人可以解释我的程序流程
import java.util.concurrent.*;
public class FutureTest {
static class MyCallable implements Callable<String> {
private long waitTime;
MyCallable(int timeInMillis){
this.waitTime=timeInMillis;
}
@Override
public String call() throws Exception {
Thread.sleep(waitTime);
return Thread.currentThread().getName();
}
}
public static void main(String[] args) throws Exception {
MyCallable callable1 = new MyCallable(500);
MyCallable callable2 = new MyCallable(1000);
FutureTask<String> futureTask1 = new FutureTask<String>(callable1);
FutureTask<String> futureTask2 = new FutureTask<String>(callable2);
ExecutorService executor = Executors.newFixedThreadPool(2);
executor.execute(futureTask2);
executor.execute(futureTask1);
while (true) {
try {
boolean done1 = futureTask1.isDone();
boolean done2 = futureTask2.isDone();
if(futureTask1.isDone() && futureTask2.isDone()){
System.out.println("Done");
executor.shutdown();
return;
}
System.out.println("Done1:" + done1 + " - 2:" + done2);
String x = futureTask1.get(100L, TimeUnit.MILLISECONDS);
if (x != null)
System.out.println("FutureTask1 output="+x);
else
System.out.println("Waiting for FutureTask1");
String s = futureTask2.get(200L, TimeUnit.MILLISECONDS);
if(s != null)
System.out.println("FutureTask2 output="+s);
else
System.out.println("Waiting for FutureTask2");
Thread.sleep(100);
} catch(TimeoutException e) {}
}
}
}
它的输出是:
Done1:false - 2:false
Done1:false - 2:false
Done1:false - 2:false
Done1:false - 2:false
Done1:false - 2:false
FutureTask1 output=pool-1-thread-2
Done1:true - 2:false
FutureTask1 output=pool-1-thread-2
Done1:true - 2:false
FutureTask1 output=pool-1-thread-2
FutureTask2 output=pool-1-thread-1
Done
为什么在Waiting for FutureTaskX
系统超时不执行?我希望主线程能够循环和系统输出Waiting for ...
,直到期货得到解决。
我对解决这个问题的不同方式不感兴趣,只是在这段代码的程序流程中。谢谢。
*请*获得使用括号甚至一个行块的习惯。它会为你节省很多错误,对于我们其他人来说更容易阅读。 – slim