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callable
1.callable是一个可以带返回值的多线程接口，类似runnable，ruannable执行无返回值的run方法，callable执行有返回值的call方法
public class CallableTest {
public static void main(String[] args) throws ExecutionException, InterruptedException {
CallClass call = new CallClass();
ExecutorService es = Executors.newFixedThreadPool(1);
Future<String> f = es.submit(() -> {
Thread.sleep(3000);
System.out.println("call Hello");
return "hello";
});
System.out.println(System.currentTimeMillis());
if (f.isDone()) {
System.out.println(f.get());
}
System.out.println(System.currentTimeMillis());
System.out.println(f.get());
System.out.println(System.currentTimeMillis());
es.shutdown();
}
}
