1.springboot2.x以前

@Configuration
@ConditionalOnProperty(value = "server.additionPort.enable", havingValue = "true")
@ConditionalOnClass(value = EmbeddedServletContainerCustomizer.class)
public class EmbeddedTomcatConfiguration implements EmbeddedServletContainerCustomizer {

    @Value("${server.additionPort.ports:}")
    private String additionalPorts;

    @Override
    public void customize(ConfigurableEmbeddedServletContainer container) {
        // 判断如果是Tomcat才进行如下配置
        if (container instanceof TomcatEmbeddedServletContainerFactory) {
            // 转类型为TomcatEmbeddedServletContainerFactory
            TomcatEmbeddedServletContainerFactory tomcat = (TomcatEmbeddedServletContainerFactory) container;
            String[] split = additionalPorts.split(",");
            for (String port : split) {
                // Tomcat中，一个Connecter监听一个端口
                // 指定协议为HTTP/1.1
                Connector httpConnector = new Connector("HTTP/1.1");
                httpConnector.setPort(Integer.parseInt(port));
                tomcat.addAdditionalTomcatConnectors(httpConnector);
            }

        }
    }

}

@Component
@ConditionalOnProperty(value = "server.additionPort.enable", havingValue = "true")
@ConditionalOnClass(value = TomcatServletWebServerFactory.class)
public class EmbeddedTomcatConfiguration {

    @Value("${server.additionPort.ports:}")
    private String additionalPorts;

    @Bean
    public TomcatServletWebServerFactory servletContainer() {
        TomcatServletWebServerFactory tomcat = new TomcatServletWebServerFactory();
        Connector[] additionalConnectors = this.additionalConnector();
        if (additionalConnectors != null && additionalConnectors.length > 0) {
            tomcat.addAdditionalTomcatConnectors(additionalConnectors);
        }
        return tomcat;
    }

    private Connector[] additionalConnector() {
        String[] ports = this.additionalPorts.split(",");
        List<Connector> result = new ArrayList<>();
        for (String port : ports) {
            Connector connector = new Connector("org.apache.coyote.http11.Http11NioProtocol");
            connector.setScheme("http");
            connector.setPort(Integer.valueOf(port));
            result.add(connector);
        }
        return result.toArray(new Connector[] {});
    }
}