MQTT is an OASIS standard messaging protocol for the Internet of Things (IoT). It is designed as an extremely lightweight publish/subscribe messaging transport that is ideal for connecting remote devices with a small code footprint and minimal network bandwidth. MQTT today is used in a wide variety of industries, such as automotive, manufacturing, telecommunications, oil and gas, etc.
This article introduces how to use MQTT in the Java project to realize the functions of connecting, subscribing, unsubscribing, publishing, and receiving messages between the client and the broker.