IDEA configures Tomcat to run Servlet projects

Analysis on the running problem of Servlet

Development stage: Configure the Tomcat plug-in in the idea, and run the idea directly after writing the code (the same process as a normal project).

Deployment stage: The developer makes a war, and then deploys the war to run on Tomcat (if it is in the development stage, it will be a little troublesome, and it needs to be packaged and released every time)

How IDEA configures the Tomcat plugin

Specific steps:
Step 1: Click Add Configuration
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Step 2: Click the "+" sign, select Tomcat, and then select local
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Step 3: Click configure to select the local Tomcat installation package, where to put your Tomcat, just select it directly

Step 4: Click the Deployment option, select the Servlet project
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Step 5: Select the project to be deployed, then click ok

Step 6: Configure the url site (modify the access path), then click ok, the configuration is complete

General preview

After configuring the Tomcat plugin, test it

Write Servlet backend class
Configure the web.xml file
Specific implementation steps:
1. Write the Servlet backend class

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;

public class MyResponseServlet extends HttpServlet {
    
    
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        //刷新操作，设置成1s刷新一次
        resp.setIntHeader("Refresh",1);
        //设置响应类型
        resp.setContentType("text/html");
        //设置编码格式,如果不设置会出现乱码
        resp.setCharacterEncoding("utf-8");
        //写入body信息
        PrintWriter writer = resp.getWriter();
        writer.println(String.format("<h1>当前时间: %s</h1>",new Date()));
    }

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

2. Configure the web.xml file

<servlet>
    <servlet-name>myResponseServlet</servlet-name>
    <servlet-class>MyResponseServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>myResponseServlet</servlet-name>
    <url-pattern>/response</url-pattern>
  </servlet-mapping>

3. Run the back-end class code in the idea, click to run, and
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a browser page will pop up by itself.
(1) When entering the url we set, a Hello World! page will appear. This page is under WEB-INF The index.jsp, this is in our project. Instead of the one that comes with Tomcat

(2) When we enter our custom url, a new interface will appear, that is, the refresh page we write, which is refreshed every second
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