我有一个处理长时间运行的HTTP请求的Jetty服务器 – 响应由不同的进程X生成,最终在Jetty请求定期检查的收集器哈希中.
有3例:
>进程X在HTTP请求的超时时间之前完成 –
没问题
>进程X在请求的超时时间结束 – 否
问题
>进程X从不完成 – 发生异常
如何检测这种情况(3)并防止异常,同时允许其他两种情况正常工作?
例外:
- 2012-06-18 00:13:31.055:WARN:oejut.QueuedThreadPool:
- java.lang.IllegalStateException: IDLE,initial
- at org.eclipse.jetty.server.AsyncContinuation.complete(AsyncContinuation.java:569)
- at server.AsyncHTTPRequestProcessor.run(AsyncHTTPRequestProcessor.java:72)
- at org.eclipse.jetty.server.handler.ContextHandler.handle(ContextHandler.java:1119)
- at org.eclipse.jetty.server.AsyncContinuation$1.run(AsyncContinuation.java:875)
- at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:599)
- at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:534)
- at java.lang.Thread.run(Thread.java:679)
Jetty继续HTTP请求:
- public class AsyncHTTPRequestProcessor implements Runnable {
- private ConcurrentHashMap<String,String> collector;
- private Logger logger;
- private AsyncContext ctx;
- //Defined this here because of strange behavIoUr when running junit
- //tests and the response json string being empty...
- private String responseStr = null;
- public AsyncHTTPRequestProcessor(AsyncContext _ctx,ConcurrentHashMap<String,String> _collector,Logger _logger) {
- ctx = _ctx;
- collector = _collector;
- logger = _logger;
- }
- @Override
- public void run() {
- logger.info("AsyncContinuation start");
- //if(!((AsyncContinuation)ctx).isInitial()){
- String rid = (String) ctx.getRequest().getAttribute("rid");
- int elapsed = 0;
- if(rid !=null)
- {
- logger.info("AsyncContinuation rid="+rid);
- while(elapsed<ctx.getTimeout())
- {
- if(collector.containsKey(rid)){
- responseStr = collector.get(rid);
- collector.remove(rid);
- logger.info("--->API http request in collector:"+responseStr);
- ctx.getRequest().setAttribute("status",200);
- ctx.getRequest().setAttribute("response",responseStr);
- ctx.getRequest().setAttribute("endTime",System.currentTimeMillis());
- //ctx.complete();
- break;
- }
- try {
- Thread.sleep(10);
- elapsed+=10;
- } catch (InterruptedException e) {
- e.printStackTrace();
- }
- }
- //}
- logger.info("Collector in async stuff:");
- for(String key:collector.keySet()){
- logger.info(key+"->"+collector.get(key));
- }
- for(Entry<String,String> x:collector.entrySet()){
- logger.info(x.getKey()+"->"+x.getValue());
- }
- ctx.complete(); <---- this line 72
- }
- }
- }
解决方法
这里的问题不是您调用AsyncContext#complete(),而是代码的泛型设计.
连续性(Servlet异步同样的事情)被设计为异步的.使用内部连续超时的while循环不能在这里.通过这样做,您正在将异步设计转变为同步设计.正确的做法是使用Continuation#addContinuationListener()注册一个监听器,并实现onTimeout()方法来适当地处理超时情况.
一旦你的超时逻辑出来,我建议将过程X逻辑移到AsyncHTTPRequestProcessor类,并从需要使用收集器移出.在处理过程中,您应该假设当前线程永远不会被超时.通过这样做,您对complete()的调用会产生敏感,您将无法收集收集器上的并发故障.