一、修改Servlet容器配置

Springboot默认servlet容器是Tomcat

1、通过yaml修改

绑定的是ServerProperties配置类
注意，这里通过配置类修改的容器设置会覆盖掉yaml的，也就是说配置类的优先级高于yaml，亲测

2、编写WebServerFactoryCustomizer配置方法

通过serlvet工厂类来修改容器配置
WebServerFactoryCustomizer：

    @Bean
    public WebServerFactoryCustomizer<ConfigurableWebServerFactory> webServerFactoryCustomizer(){
        return new WebServerFactoryCustomizer<ConfigurableWebServerFactory>(){
            @Override
            public void customize(ConfigurableWebServerFactory factory) {
                factory.setPort(8081);
            }
        };
    }

二、注册三大组件

1、注册Servlet

首先编写一个servlet
MyServlet：

public class MyServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().println("My servlet");
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}

在配置类中注入bean
ServletRegistrationBean ：

    @Bean
    public ServletRegistrationBean myServlet(){
        return new ServletRegistrationBean(new MyServlet(),"/myServlet");
    }

Springboot自动装配的SpringMVC中的DispatcherServlet也是通过RegistrationBean进行自动配置

DispatcherServletRegistrationConfiguration：

    @Configuration(proxyBeanMethods = false)
    @Conditional(DispatcherServletRegistrationCondition.class)
    @ConditionalOnClass(ServletRegistration.class)
    @EnableConfigurationProperties(WebMvcProperties.class)
    @Import(DispatcherServletConfiguration.class)
    protected static class DispatcherServletRegistrationConfiguration {

        @Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
        @ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
        public DispatcherServletRegistrationBean dispatcherServletRegistration(DispatcherServlet dispatcherServlet,
                WebMvcProperties webMvcProperties, ObjectProvider<MultipartConfigElement> multipartConfig) {
            DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(dispatcherServlet,
                    webMvcProperties.getServlet().getPath());
            registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
            registration.setLoadOnStartup(webMvcProperties.getServlet().getLoadOnStartup());
            multipartConfig.ifAvailable(registration::setMultipartConfig);
            return registration;
        }

    }

默认的path：private String path = "/";

2、注册Filter

编写一个Filter：

public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("do filter...");
        filterChain.doFilter(servletRequest, servletResponse);
    }

    @Override
    public void destroy() {

    }
}

通过配置类注入Bean：

    @Bean
    public FilterRegistrationBean myFilter(){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new MyFilter());
        filterRegistrationBean.setUrlPatterns(Arrays.asList("/myServlet","/filter"));
        return filterRegistrationBean;
    }

3、注册Litener

编写一个Litener：

public class MyListener implements ServletContextListener {
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("web init");
    }

    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("web destroy");
    }
}

通过配置类注入Bean：

    @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletListenerRegistrationBean listenerRegistrationBean = new ServletListenerRegistrationBean(new MyListener());
        return listenerRegistrationBean;
    }

三、切换其他Serlvet容器

在pom中排除spring-boot-starter-tomcat，并且加入jetty的启动器

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                    <groupId>org.springframework.boot</groupId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <artifactId>spring-boot-starter-jetty</artifactId>
            <groupId>org.springframework.boot</groupId>
        </dependency>