这个问题与 com.jayway.awaitility.Awaitility 有关。
我刚刚尝试了 Awaitility.await() ,它似乎有一些奇怪的行为。在下面的测试方法中,如果我注释掉 testWithFuture() 并启用 testWithAwaitility(),我永远不会看到打印出消息“结束”。我看到“开始”,然后程序就退出了,第二个打印语句似乎永远不会到达。
因此,作为一种变通方法,我决定使用 Settable{Future}.. 如果其他人有同样的问题,那么我提供的变通方法可能会很有用.. 更好的是得到一个好的答案;^)!在此先感谢/克里斯
编码:
import com.google.common.util.concurrent.SettableFuture;
import java.util.Date;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import static com.jayway.awaitility.Awaitility.await;
import static java.util.concurrent.TimeUnit.SECONDS;
public class AwaitTest {
static volatile boolean done = false;
public static void main(String[] args) throws InterruptedException, ExecutionException, TimeoutException {
testWithFuture();
//testWithAwaitility();
}
private static void testWithAwaitility() {
System.out.println("start " + new Date());
new Thread(new Runnable(){
public void run(){
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
done = true;
}
}).start();
await().atMost(2, SECONDS).until(new Callable() {
@Override
public Boolean call() throws Exception {
return done;
}
});
System.out.println("end " + new Date()); // NEVER Reached. i wonder why?
}
// This does what I want.
//
private static void testWithFuture() throws InterruptedException, ExecutionException, TimeoutException {
System.out.println("start testWithFuture");
final SettableFuture future = SettableFuture. create();
new Thread(new Runnable(){
public void run(){
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
future.set("Hello");
}
}).start();
String result = future.get(4, TimeUnit.SECONDS);
if (! result.equals("Hello")) {
throw new RuntimeException("not equal");
} else {
System.out.println("got Hello");
}
}
}
更正的代码->
import java.util.Date;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import static com.jayway.awaitility.Awaitility.await;
import static java.util.concurrent.TimeUnit.SECONDS;
public class Sample {
static volatile boolean done = false;
public static void main(String[] args) {
testWithAwaitility();
}
private static void testWithAwaitility() {
System.out.println("start " + new Date());
new Thread(new Runnable(){
public void run(){
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
done = true;
}
}).start();
try {
await().atMost(2, SECONDS).until(new Callable() {
@Override
public Boolean call() throws Exception {
return done;
}
});
} catch (Exception e) {
System.out.println("FAILED");
e.printStackTrace();
}
System.out.println("end " + new Date()); // REACHED this statement after correction
}
}