1. A message publishing method comprising: obtaining a message that a publisher has sent to a dummy topic corresponding to the publisher; searching for, according to a stored routing rule, all transmission paths with the dummy topic corresponding to the publisher being a start point and the dummy topic corresponding to any one subscriber being an end point, wherein the dummy topic is configured to forward a message between the actual topic, and wherein the actual topic is configured to forward a message between the publisher and the subscriber; transmitting the message or identification information corresponding to the message on a found transmission path when the transmission path with the dummy topic corresponding to the publisher being the start point and the dummy topic corresponding to any one subscriber being the end point is found; and sending the message to a subscriber corresponding to the end point of the transmission path after the message or the identification information corresponding to the message is transmitted to an end point of each transmission path.