springboot_ two ways of servlet

Although we use in springboot Controller can meet most needs, but servlet, etc. are also essential.

Use the servlet springboot in two ways:

The first:

1. Creating a servlet with the annotation mode, and declares its url in a comment
2. Add @ServletComponentScan ( "com.rong.interceptor.servlet") on the Application class, which is the path of notes in the servlet created.

package com.rong.interceptor.servlet;

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;

@WebServlet("/myservlet")
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       resp.getWriter().write("hello");
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req,resp);
    }
}

@SpringBootApplication
@ServletComponentScan("com.rong.interceptor.servlet")
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

The second (this way except that no @ServletComponentScan):

1. Still we have to create a servlet, the same as above except that no @WebServlet comment.
2. Then create a servlet class configuration, and add the url in the configuration class

package com.rong.interceptor.servlet;

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 MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       resp.getWriter().write("hello");
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req,resp);
    }
}

package com.rong.interceptor.config;

import com.rong.interceptor.servlet.MyServlet;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class ServletConfig {

    @Bean
    public ServletRegistrationBean myServletRegistration(){
        ServletRegistrationBean registration = new ServletRegistrationBean(new MyServlet());
        registration.addUrlMappings("/myservlet");
        return registration;
    }
}