[springboot] Running parameter configuration of embedded tomcat container (including video)

In the Spring Boot project, web application service containers such as Tomcat, Jetty, and Undertow can be supported. When we add the spring-boot-starter-web dependency, Tomcat will be used as the embedded web container by default, and we don't need to deploy it separately. The web application can be run as a jar package.

Two configuration methods for adjusting the parameters of the SpringBoot application container

• Modify the configuration file (simple)
• Custom configuration class (professional tuning)

Text video

Running parameter configuration of embedded tomcat container

1. Configuration file method

In application.properties/application.yml, you can configure the properties required for the operation of the web container. You can view all the configuration items about the server on the official website through this link: server-properties .

• The beginning of server.xx is the configuration common to all servlet containers,
• Server.tomcat.xx starts with configuration parameters specific to the tomcat container
• Server.jetty.xx starts with configuration parameters specific to the Jetty container
• Server.undertow.xx starts with the configuration parameters specific to the undertow container

1.1. Common configuration parameters

parameter	Defaults	illustrate
server.port	8080	Configure the port number of the web container
server.servlet.session.timeout	30m (30 minutes)	Session expiration time. If no unit is written, the default unit is seconds. (Note: Since the session expiration time configured in Tomcat is in minutes, if the setting here is seconds, it will be automatically converted to a maximum number of minutes that does not exceed the configured seconds. For example, 119 seconds (1 minute 59 seconds) is configured ), then the actual session expiration time is 1 minute)
server.servlet.context-path	/	The base path of the URL access path
server.tomcat.uri-encoding	UTF-8	Configure Tomcat request encoding
server.tomcat.basedir		Configure the directory for Tomcat run logs and temporary files. If not configured, the system's temporary directory will be used by default.

1.2. Tomcat performance optimization core parameters

The working principle of the tomcat connector:

• A request receiving queue is maintained before the Acceptor. The maximum length of the queue is: the maximum number of request connections that tomcat can accept: server.tomcat.max-connections.
• Acceptor listens for connection requests and generates a SocketProcessor task and submits it to the thread pool for processing
• When all threads in the thread pool are occupied, the newly created SocketProcessor task is put into the waiting queue, and the maximum degree of waiting for the queue: server.tomcat.accept-count
• The server.tomcat.threads.max of the thread pool determines the limit SocketProcessor task processing capability of tomcat. It's not that bigger is better. The more threads, the more resources are consumed.
• The server.tomcat.threads.min-spare of the thread pool reserves a certain number of threads in the thread pool when the application is idle. Avoid time-wasting by temporarily creating threads after the request arrives.

parameter	Defaults	illustrate
server.tomcat.max-connections	8192	Maximum number of requested connections accepted
server.tomcat.accept-count	100	When all threads are occupied, the maximum number of request connections that are put into the request queue and wait
server.tomcat.threads.max	200	Maximum number of worker thread pools
server.tomcat.threads.min-spare	10	Minimum number of worker thread pools

Second, the custom configuration class

Steps:
1. Create a configuration class and add @Configuration annotation
2. Add the customizer ConfigurableServletWebServerFactory
3. Return the customizer

@Configuration
public class TomcatCustomizer {
    
    

    @Bean
    public ConfigurableServletWebServerFactory configurableServletWebServerFactory(){
    
    
        TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
        factory.addConnectorCustomizers(new MyTomcatConnectionCustomizer());
        return factory;
    }


    static class MyTomcatConnectionCustomizer implements TomcatConnectorCustomizer {
    
    

        public MyTomcatConnectionCustomizer() {
    
    
        }

        @Override
        public void customize(Connector connector) {
    
    
            connector.setPort(Integer.parseInt("8888"));
            connector.setProperty("maxConnections", "8192");
            connector.setProperty("acceptorThreadCount", "100");
            connector.setProperty("minSpareThreads", "10");
            connector.setProperty("maxThreads", "200");
        }
    }
}

This approach is more customizable and more flexible. However, you need to have a deep understanding of the underlying implementation principle and design mechanism of the server container, and you also need to have a certain API proficiency of TomcatServletWebServerFactory.

more flexible. However, you need to have a deep understanding of the underlying implementation principle and design mechanism of the server container, and you also need to have a certain API proficiency of TomcatServletWebServerFactory.