EmbeddedTomcatTest.java

package demo;

import java.util.Arrays;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;

import org.apache.catalina.LifecycleListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
import org.springframework.boot.context.embedded.ServletContextInitializer;
import org.springframework.boot.context.embedded.tomcat.ServletContextInitializerLifecycleListener;
import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
    
    @Bean
    public EmbeddedServletContainerFactory servletContainer() {
        TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory();
        ServletContextInitializer ctxtInitializer = new MyServletContextInitializer();
        LifecycleListener listener = new ServletContextInitializerLifecycleListener(ctxtInitializer);
        tomcat.setContextLifecycleListeners(Arrays.asList(listener));
        return tomcat;
    }

}

class MyServletContextInitializer implements ServletContextInitializer {
    
    private static final Log log = LogFactory.getLog(MyServletContextInitializer.class);

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
       log.info("the tomcat starts up"); 
    }

}