NPE by getDeliverTimeMs

[dousp]

当DelayMode不是DELIVER_TIME_MILLISECONDS时，将Message对象toJSONString时，导致 Long.parseLong 抛出 NumberFormatException异常

Message中如下方法，this.getUserProperty(MessageConst.PROPERTY_TIMER_DELIVER_MS)返回了null.

public long getDeliverTimeMs() {
        return Long.parseLong(this.getUserProperty(MessageConst.PROPERTY_TIMER_DELIVER_MS));
 }

RocketMQTemplate中：

public SendResult syncSend(String destination, Message<?> message, long timeout) {
        return syncSend(destination, message, timeout, 0);
    }