What is the purpose of the AJP protocol in Tomcat?

In Tomcat, the AJP (Apache JServ Protocol) protocol is mainly used to facilitate communication between the Tomcat server and the front-end web server (such as Apache server). Through the AJP protocol, the Tomcat server can receive HTTP requests from the front-end web server and send back the processing results, thus enabling collaboration and load balancing between the Tomcat server and the front-end web server. The AJP protocol is known for its efficiency, lightweight nature, and low latency, making it suitable for improving the performance and stability of web applications.