这是我参与11月更文挑战的第15天，活动详情查看：2021最后一次更文挑战 大家都知道我们的SpringBoot使用的Tomcat是内置的，向我们之前使用tomcat是外置的，我们可以自定义tomcat配置，但是SpringBoot怎么办呢？

1、修改和server有关的配置（ServerProperties【也是EmbeddedServletContainerCustomizer】）；

server.port=8081
server.context-path=/crud

server.tomcat.uri-encoding=UTF-8

//通用的Servlet容器设置
server.xxx
//Tomcat的设置
server.tomcat.xxx

2、编写一个EmbeddedServletContainerCustomizer：嵌入式的Servlet容器的定制器；来修改Servlet容器的配置

/**
     * 配置嵌入式的servlet容器
     * @return
     */
    @Bean
    public WebServerFactoryCustomizer<ConfigurableWebServerFactory> customizer(){
        return new WebServerFactoryCustomizer<ConfigurableWebServerFactory>() {

            //定制嵌入式的Servlet容器
            @Override
            public void customize(ConfigurableWebServerFactory factory) {
                factory.setPort(8080);
            }
        };

    }

然后我们再写一个三大件

首先是我们的Servlet，创建一个类

public class MyServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            response.getWriter().write("Hello MyServlet");
    }

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

一个正常的Servlet

然后监听器

public class MyListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("web应用启动");
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("web应用关闭");
    }
}

过滤器

public class MyFiler implements Filter {


    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        Filter.super.init(filterConfig);
    }

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

    @Override
    public void destroy() {
        Filter.super.destroy();
    }
}

创建一个Servlet的配置类

@Configuration
public class MyServerConfig {

    /**
     * 注册三大组件
     */
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean registrationBean = new ServletRegistrationBean(new MyServlet(), "/myServlet");

        return  registrationBean;
    }


    @Bean
    public FilterRegistrationBean mtFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new MyFiler());
        registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
        return  registrationBean;
    }

    @Bean
    public ServletListenerRegistrationBean myListener(){
        ServletListenerRegistrationBean<MyListener> myListenerServletListenerRegistrationBean = new ServletListenerRegistrationBean<>(new MyListener());
        return myListenerServletListenerRegistrationBean;
    }



    /**
     * 配置嵌入式的servlet容器
     * @return
     */
    @Bean
    public WebServerFactoryCustomizer<ConfigurableWebServerFactory> customizer(){
        return new WebServerFactoryCustomizer<ConfigurableWebServerFactory>() {

            //定制嵌入式的Servlet容器
            @Override
            public void customize(ConfigurableWebServerFactory factory) {
                factory.setPort(8080);
            }
        };

    }
}

SpringBoot帮我们自动SpringMVC的时候，自动的注册SpringMVC的前端控制器；DIspatcherServlet；

DispatcherServletAutoConfiguration中：

@Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
@ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
public ServletRegistrationBean dispatcherServletRegistration(
      DispatcherServlet dispatcherServlet) {
   ServletRegistrationBean registration = new ServletRegistrationBean(
         dispatcherServlet, this.serverProperties.getServletMapping());
    //默认拦截： /  所有请求；包静态资源，但是不拦截jsp请求；   /*会拦截jsp
    //可以通过server.servletPath来修改SpringMVC前端控制器默认拦截的请求路径
    
   registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
   registration.setLoadOnStartup(
         this.webMvcProperties.getServlet().getLoadOnStartup());
   if (this.multipartConfig != null) {
      registration.setMultipartConfig(this.multipartConfig);
   }
   return registration;
}

其他嵌入式Servlet容器

tomcat

我们都知道我们的默认支持：Tomcat

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

引入web模块默认就是使用嵌入式的Tomcat作为Servlet容器；

jetty

<!--引入Web模块-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <!--排除tomcat-->
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

<!--引入其他Servlet容器-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>

undertow

 <!--引入其他Servlet容器-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-undertow</artifactId>
        </dependency>