Java 重头戏1.3事件流实现

因此，我一直在尝试使用Play Framework 1.3实现一个合适的EventStream解决方案，但我就是无法让它正常工作。不断抛出异常，但我不确定原因是什么

有谁能提供一个示例实现或为我指出一个方向

这是我在控制器中使用的方法

public static void stream() {
    response.contentType = "text/event-stream";
    response.encoding = "UTF-8";
    response.status = 200;
    response.chunked = true;

    // a record of the last ID that this request... requested
    Long lastId = 0L;

    // since this request has only been initiated, the first thing to do is return a list of whats in the queue
    List<F.IndexedEvent> archive = StreamQueue.getRecentNotifications(lastId);
    if (!archive.isEmpty()) {
        // write that list out in the response
        response.writeChunk(//a string representing the entire list as a single event);
        // update out internal reference to the lastId
        lastId = archive.get(archive.size() - 1).id;
    }

    // keep this connection alive
    while (true) {
        // await the promise of more notifications for the stream
        List<F.IndexedEvent<StreamQueue.Notification>> notifications = await(StreamQueue.getNextNotification(lastId));
        // for each notification, write it out as a separate event
        for (int i = 0; i < notifications.size(); i++) {
            response.writeChunk(//a string representing a single event using notifications.get(i));
            // update out internal reference to the lastId
            lastId = notifications.get(i).id;
        }
    }
}

异常似乎是由于我从

StreamQueue.getNextNotification（…）

调用的

ArchivedEventStream.nextEvents（…）

而引发的。原因似乎是

Long

被转换为

Map

，但我从未尝试这样做

提前感谢您的帮助

更新

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所以我在Play 1.2.5中尝试了我的项目，流媒体效果非常好。但是，项目要求我们使用播放1.3。

原因在堆栈跟踪的底部：

Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to java.util.Map

---

我认为您正在尝试强制转换

通知。时间戳

映射到

StreamController

时间戳实际上没有被使用（以前代码的遗留部分），但异常似乎发生在ArchivedEventStream.nextEvents（…）；

Internal Server Error (500) for request GET /stream

Execution exception
InvocationTargetException occured : null

play.exceptions.JavaExecutionException
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:230)
    at Invocation.HTTP Request(Play!)
Caused by: java.lang.reflect.InvocationTargetException
    at play.mvc.ActionInvoker.invokeWithContinuation(ActionInvoker.java:524)
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:475)
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:451)
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:446)
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:160)
    ... 1 more
Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to java.util.Map
    at controllers.StreamController.stream(StreamController.java)
    ... 6 more

Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to java.util.Map