修改servlet有關的配置(ServerProperties)
例如在application.properties
    server.port=8081
    server.context-path=/crud
    server.tomcat.uri-encoding=utf-8

1.通用的servlet容器設定
    server.xxx
2.tomcat的設定
    server.tomcat.xxx
    
    
3.還可以通過嵌入式的servlet容器定製器(WebServerFactoryCustomizer),來修改容器的配置
    @Configuration
    public class MyServerConfig {
        @Bean
        public WebServerFactoryCustomizer WebServerFactoryCustomizer(){
            return new WebServerFactoryCustomizer() {
                @Override
                public void customize(WebServerFactory factory) {
                    ConfigurableWebServerFactory factory1= (ConfigurableWebServerFactory) factory;
                    factory1.setPort(8083);
                }
            };
        }
    }

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如何註冊servlet的三大元件
由於springbootmore是以jar包的形式啟動嵌入式的servlet容器來啟動springboot的web應用，沒有web.xml檔案，註冊三大元件(servlet,filter,listener)以以下的方式

1.註冊servlet
    1.1 建立自己的servlet，處理doget/dopost請求
        public class Myservlet extends HttpServlet {
            @Override
            protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
                doPost(req,resp);
            }
            @Override
            protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
                resp.getWriter().println("hello myservlet");
            }
        }
    1.2.配置servlet並載入到容器中
        @Configuration
            public class MyServerConfig {
                //配置嵌入式的servlet：設定埠為8083
                @Bean
                public WebServerFactoryCustomizer webServerFactoryCustomizer(){
                    return new WebServerFactoryCustomizer() {
                        @Override
                        public void customize(WebServerFactory factory) {
                            ConfigurableWebServerFactory factory1= (ConfigurableWebServerFactory) factory;
                            factory1.setPort(8083);
                        }
                    };
                }
                //配置servlet的三大元件
                //1.註冊servlet
                @Bean
                public ServletRegistrationBean myservlet(){
                    //使用ServletRegistrationBean：引數1(自己的servlet)，引數2(自建的servlet處理的請求路徑)
                    ServletRegistrationBean registrationBean = new ServletRegistrationBean(new Myservlet(), "/myservlet");
                    return registrationBean;
                }
            }
    1.3訪問路徑：http://localhost:8083/myservlet  頁面出現：hello myservlet  說明自建的servlet起作用了，配置成功！
    
2.註冊filter
    2.1建立自己的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("MyFilter process");
                filterChain.doFilter(servletRequest, servletResponse);
            }
            @Override
            public void destroy() {
        
            }
        }
    2.2將自己的filter註冊到容器中
        //註冊filter
        @Bean
        public FilterRegistrationBean myFilter(){
            FilterRegistrationBean registrationBean=new FilterRegistrationBean();
            registrationBean.setFilter(new Myfilter());
            registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
            return registrationBean;
        }
    2.3.當輸入路徑是：http://localhost:8083/myServlet  後臺列印：MyFilter process
    
3.註冊listener
    3.1自己建立的lister
        public class MyListener implements ServletContextListener {
            @Override
            public void contextInitialized(ServletContextEvent sce) {
                System.out.println("ServletContex物件初始化...web應用啟動！");
            }
        
            @Override
            public void contextDestroyed(ServletContextEvent sce) {
                System.out.println("ServletContex銷燬...伺服器關閉！");
            }
        }
    3.2將自己建立的listener載入到容器中
        //註冊listener
        @Bean
        public ServletListenerRegistrationBean myListener(){
            ServletListenerRegistrationBean listenerRegistrationBean=new ServletListenerRegistrationBean(new MyListener());
            return listenerRegistrationBean;
        }
    3.3
        當程式啟動時：列印：ServletContex物件初始化...web應用啟動！
        當程式正常停止時：列印：ServletContex銷燬...伺服器關閉！
 

1.tomcat(預設使用)
2.Jetty(長連線)
3.Undertow(不支援jsp)