ServletRegistrationBean 注册
Servlet组件扫描
ServletContextInitializer 动态注册



SpringBoot 提供ServletRegistrationBean, FilterRegistrationBean, ServletListenerRegistrationBean 
分别注册 Servlet, Filter, Listener

    
@Bean
public ServletRegistrationBean registerHelloServlet() {
    ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new HelloServlet(), "/hello");
    servletRegistrationBean.addInitParameter("name", "dyyx");
    return servletRegistrationBean;
}



Servlet3.0 之前，Servlet Filter Listener 在 web.xml 中配置
Servlet3.0之后 可基于代码或注解配置
@WebServlet  
@WebFilter 
@WebListener 

@WebServlet(name = "helloServlet2", urlPatterns = "/hello2", asyncSupported = true,
initParams = {@WebInitParam(name = "name", value = "dyyx"),})
public class HelloServlet2 extends HttpServlet {

注意！！！
使用内嵌容器 ，需要开启 Servlet 组件扫描 @ServletComponentScan


@SpringBootApplication
@ServletComponentScan
public class App {



org.springframework.boot.web.servlet.ServletContextInitializer

@Component
public class ServletInitBean implements ServletContextInitializer{
    @Override
    public void onStartup(ServletContext servletContext) {
        ServletRegistration initServlet = servletContext
                .addServlet("helloServlet3", HelloServlet3.class);
        initServlet.addMapping("/hello3");
        initServlet.setInitParameter("name", "dyyx");
    }
}




完整代码
https://gitee.com/dyyx/demos/tree/master/springboot_servlet