一、使用注解方式

1、使用Servlet3注解方式写一个Servlet

@WebServlet(urlPatterns = "/myServlet")
public class MyServlet extends HttpServlet {
    private static final long serialVersionUID = -4316351735748478174L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().println("my servlet hello world");
        resp.getWriter().flush();
        resp.getWriter().close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

2、在main方法添加注解扫描servlet

@ServletComponentScan(basePackages = "com.example.springboot.servlet")

二、通过SpringBoot配置类实现

1、编写一个普通servlet类

public class HeServlet extends HttpServlet {
    private static final long serialVersionUID = -4316351735748478173L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().println("he servlet hello world");
        resp.getWriter().flush();
        resp.getWriter().close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

2、编写一个springboot配置类

@Configuration
public class ServletConfig {

    @Bean
    public ServletRegistrationBean heServletRegistrationBean() {
        ServletRegistrationBean registration = new ServletRegistrationBean(new HeServlet(),"/heServlet");
        return registration;
    }
}