Spring发送事件- ResponseBodyEmitter已经设置完成
Spring发送事件- ResponseBodyEmitter已经设置完成
提问于 2017-03-16 13:46:09
我使用spring 4.3.7.RELEASE来设置服务器发送的事件。并使用@scheduled注释每2秒发送一次消息。这是控制器。
@Controller
public class MySSEController {
private final SseEmitter sseEmitter = new SseEmitter();
private int counter = 0;
@RequestMapping("/ssestream")
public SseEmitter getRealTimeMessageAction() throws IOException {
sseEmitter.send("MessageCounter : " + counter);
return sseEmitter;
}
@Scheduled(fixedDelay = 2*1000)
public void scheduledMsgEmitter() throws IOException
{
if(null != sseEmitter) {
sseEmitter.send("MessageCounter : " + ++counter);
}
}
}我是从eclipse直接在Tomcat 9上运行这个的。应用程序每2次启动并向浏览器发送消息。但是过了一段时间，它停止发送消息，我在eclipse控制台中看到了下面的异常。
Mar 16, 2017 6:57:34 PM org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver handleAsyncRequestTimeoutException
SEVERE: Async timeout for GET [/streaming-web/stream/ssestream]
Mar 16, 2017 6:57:35 PM org.springframework.scheduling.support.TaskUtils$LoggingErrorHandler handleError
SEVERE: Unexpected error occurred in scheduled task.
java.lang.IllegalStateException: ResponseBodyEmitter is already set complete
at org.springframework.util.Assert.state(Assert.java:70)
at org.springframework.web.servlet.mvc.method.annotation.ResponseBodyEmitter.send(ResponseBodyEmitter.java:158)
at org.springframework.web.servlet.mvc.method.annotation.SseEmitter.send(SseEmitter.java:126)
at org.springframework.web.servlet.mvc.method.annotation.SseEmitter.send(SseEmitter.java:107)
at org.springframework.web.servlet.mvc.method.annotation.SseEmitter.send(SseEmitter.java:89)
at com.mycomp.test.controllers.MySSEController.scheduledMsgEmitter(MySSEController.java:25)
at sun.reflect.GeneratedMethodAccessor31.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:65)
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)我是不是遗漏了什么？请帮我解决这个问题。
回答 4
Stack Overflow用户
发布于 2017-07-27 12:55:09
我不确定这是否是正确的解决方案.
我稍微修改了实现，使其与所有连接的客户端( 之前，我无法向连接到此流的不同客户端传递相同的消息。 )一起工作--这个实现不抛出IllegalStateException。
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
@Controller
public class MySSEController_Working {
private Set<SseEmitter> sseEmitters = new HashSet<SseEmitter>();
private int messageCount = 0;
@RequestMapping("/ssestream")
public SseEmitter getRealTimeMessageAction(HttpServletRequest request, HttpServletResponse response) throws IOException {
final SseEmitter sseEmitter = new SseEmitter();
sseEmitter.onCompletion(() -> {
synchronized (this.sseEmitters) {
this.sseEmitters.remove(sseEmitter);
}
});
sseEmitter.onTimeout(()-> {
sseEmitter.complete();
});
// Put context in a map
sseEmitters.add(sseEmitter);
return sseEmitter;
}
@Scheduled(fixedDelay = 2*1000)
public void scheduledMsgEmitter() throws IOException
{
if(!sseEmitters.isEmpty())
++messageCount;
else
System.out.println("No active Emitters ");
System.out.println("Sent Messages : " + messageCount);
sseEmitters.forEach(emitter -> {
if (null != emitter)
try {
System.out.println("Timeout : "+ emitter.getTimeout());
emitter.send("MessageCounter : " + messageCount);
emitter.complete();
} catch (IOException e) {
e.printStackTrace();
}
});
}
}Stack Overflow用户
发布于 2017-11-10 23:08:33
SseEmitter超时以毫秒为单位: 60001是60秒。这是一个会话超时，不受会话活动的影响。
超时需要设置为会话的预期持续时间，以毫秒为单位。因此，86400000 (或更多)是完全合适的。
Stack Overflow用户
发布于 2022-10-07 16:02:34
我在没有完成事件的情况下使用new org.springframework.web.servlet.mvc.method.annotation.SseEmitter(0L)。
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原文链接：
https://stackoverflow.com/questions/42835888
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