SpringBoot-Servlet容器、组件学习

一、配置嵌入式的Servlet容器

背景：
SpringBoot默认使用Tomcat作为嵌入式的Servlet容器
思考：
1）SpringBoot中如何定制和修改Servlet容器的相关配置？
1、在配置文件中配置server

server.port=8080
server.servlet.context-path=/crud
server.tomcat.uri-encoding=GBK
//通用的Servlet容器设置
server.xxx
//Tomcat设置
server.tomcat.xxx

2、编写一个嵌入式的Servlet容器的定制器（WebServerFactoryCustomizer）；来修改配置

@Bean
    public WebServerFactoryCustomizer<ConfigurableWebServerFactory> webServerFactoryCustomizer()
    {
     
        return new WebServerFactoryCustomizer<ConfigurableWebServerFactory>() {
     
            //定制嵌入式的Servlet容器相关规则
            @Override
            public void customize(ConfigurableWebServerFactory factory) {
     
                factory.setPort(8083);
            }
        };
    }

题外话：

二、注册Servlet、Filter、Listener

1）注册Servlet（ServletRegistrationBean）
配置类：

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

MyServlet类：

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().write("Hello,MyServlet");
    }
}

2）注册Filter
alt+Enter是返回变量快捷键

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

3）注册Listener

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

三、其他的嵌入式Servlet容器

Tomcat
Jetty（长连接）
Undertow（不支持JSP）
SpringBoot默认可切换以上2个容器

1、切换jetty，删除tomcat相关依赖，加入jetty依赖

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

2、Undertow

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

3、引入web模块默认使用tomcat