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Servlet student management system (Mengxin hands-on version)

2022-06-29 18:09:00 【Soup key TJ】

Catalog

Introduce
Implementation steps
1. Create a web project
2. Create a... To save student information HTML file
3. Create a class , Inherit HttpServlet
4. rewrite doGet and doPost Method
5. stay web.xml File to modify the default home page and configuration Servlet( To modify the default home page is to configure the default home page to the one just created HTML file )
6. stay doGet Method to save the form data to a file , And respond to the browser results
7. Deploy and launch the project
8. Pass the browser test
Concrete realization
action Location ： Virtual path + Resource access path
stay HttpServletRequest in
request.getParameter() Method
adopt name Get the corresponding value for the property name of
1. Get through http Data submitted by agreement . Through the implementation of the container get perhaps post Data submitted by
2.request.getParameter() Method passed data , From web Client to web Server side , representative HTTP Request data , This method returns String Data of type
HTML The file is kept in web In the catalog

package com.example.servletdemo1;

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


public class HelloServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // Get form data 
        String username = request.getParameter("username");
        String age = request.getParameter("age");
        String score = request.getParameter("score");
    // Use character output stream 
        BufferedWriter bw = new BufferedWriter(new FileWriter("D:\\test\\my\\tj.txt",true));
        bw.write(username+","+age+","+score);
        bw.newLine();
        bw.close();
   // Respond to client browser 
        PrintWriter pw = response.getWriter();
        pw.println("Save Success");
        pw.close();
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!--  Modify the default home page  -->
    <welcome-file-list>
        <welcome-file>/addStudent.html</welcome-file>
    </welcome-file-list>
    <!--  To configure Servlet -->
    <servlet>
        <servlet-name>studentServlet</servlet-name>
        <servlet-class>com.example.servletdemo1.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>studentServlet</servlet-name>
        <url-pattern>/cpc</url-pattern>
    </servlet-mapping>
</web-app>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title> Save student information </title>
</head>
<body>
  <form action="/demo2/cpc" method="get" autocomplete="off">
     The student's name ：<input type="text" name="username"> <br/>
     Student age ：<input type="number" name="age"> <br/>
     Student achievement ：<input type="number" name="score"> <br/>
    <button type="submit"> preservation </button>
  </form>
</body>
</html>