张孝祥Callable&Future(学习笔记)

package cn.javaious.concurrence;

import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class CallableAndFuture {

public static void main(String[] args) {
// TODO Auto-generated method stub
ExecutorService threadPool = Executors.newSingleThreadExecutor();
Future<String> future = threadPool.submit(new Callable<String>() {
@Override
public String call() throws Exception {
// TODO Auto-generated method stub
return "hello";
}
});
System.out.println("waiting for output...");
try {
System.out.println("get result "+future.get());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
ExecutorService threadPool2 = Executors.newFixedThreadPool(10);
CompletionService<Integer> completionService = new ExecutorCompletionService<Integer>(threadPool);
for(int i=1;i<10;i++) {
final int seq = i;
completionService.submit(new Callable<Integer>() {
@Override
public Integer call() throws Exception {
// TODO Auto-generated method stub
Thread.sleep(new Random().nextInt(5000));
return seq;
}
});
}
for(int i=0;i<10;i++) {
try {
System.out.println(completionService.take().get());
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

}