/** 异步等待消息 */
private void waitMessage(HttpServletRequest request) {
try {
AsyncContext ac = request.startAsync();
ac.setTimeout(this.asyncTimeout);
ac.addListener(new AsyncAdapter() {
@Override
public void onError(AsyncEvent asyncevent) throws IOException {
close();
PushException e = new PushException("async context error!");
fireError(e);