SpringBoot 官方文档示例：(62) ServletContextInitializer的用法

可以通过ServletContextInitializer来向容器注册Servlet
一、定义Servlet

package com.example.config;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class MyServlet3 extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getOutputStream().println("hello world3...");
    }
}

二、注册Servlet

package com.example.config;

import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.context.annotation.Configuration;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;

@Configuration
public class MyServletContextInitializer implements ServletContextInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        servletContext.addServlet("myServlet3", new MyServlet3()).addMapping("/welcome3");
    }
}

三、postman测试：