Servlet user management system continues to develop

One, added to the database query to verify:

1. Create a database user

create table user(
id int primary key,
username varchar(32) not null,
email varchar(64),
grade int default 1,
password varchar(32) not null
)

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 Use database for verification

ControlServlet.java

package com.controller;

import java.io.IOException;
import java.io.PrintWriter;

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 javax.xml.ws.Response;
import java.sql.*;
import com.test.TestServlet;

/**
 * Servlet implementation class ControlServlet
 */
@WebServlet("/ControlServlet")
public class ControlServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public ControlServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        request.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();
        String id = request.getParameter("id");
        Password String = request.getParameter ( " password " );
         // in the database to verify 
            Connection Conn = null ;
            PreparedStatement ps = null;
            Statement stmt = null;
            RS the ResultSet = null ;
             the try { // load drive 
                the Class.forName ( " com.mysql.jdbc.Driver " );
            } catch (ClassNotFoundException e) {
                e.printStackTrace ();
                . System OUT .println ( " Failed to establish connection " );
            }

            the try { // create a connection object 
                Conn the DriverManager.getConnection = ( " JDBC: MySQL: // localhost: 3306 / User " , " the root " , " 123456 " );
                stmt = conn.createStatement (); // create an object sql operation 
                PS = conn.prepareStatement ( " the SELECT * from the User password and the WHERE the above mentioned id = =?? " );
                 // assignment 
                ps.setObject ( 1 , the above mentioned id);
                ps.setObject(2, password);
RS = ps.executeQuery ();
                IF (rs.next ()) {
                   // the legitimate user 
                   Response.sendRedirect ( " / User / the MainFrame " );
               }else{
                   response.sendRedirect("/user/Loin");
               }
            } catch (SQLException e) {
                e.printStackTrace ();
                . System OUT .println ( " Failed to establish connection " );
            } finally {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace ();
                }

            }

    
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

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LgionServlet.java

package com.view;

import java.io.IOException;
import java.io.PrintWriter;

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

/**
 * Servlet implementation class Loin
 */
@WebServlet("/Loin")
public class LoinServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoinServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //浏览器uft-8展示
        response.setContentType("text/html;charset=utf-8");
        response.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
        //返回一个界面
//        out.println("你好");
        out.println("<h1>用户登录</h1>");
        out.println("<form action='/user/ControlServlet' method='post'>");
        out.println("id:<input type='text' name='id'></br>");
        out.println("密 码:<input type='password' name='password'></br>");
        out.println("<input type='submit' value='登录'></br>");
        out.println("</form>");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request,response);
    }

}

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MainFrame.java

package com.view;

import java.io.IOException;
import java.io.PrintWriter;

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 com.test.TestServlet;

/**
 * Servlet implementation class MainFrame
 */
@WebServlet("/MainFrame")
public class MainFrame extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public MainFrame() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();
        String username=request.getParameter("uname");
        USERNAME2 String = (String) Request.getSession () the getAttribute (. " LoginUser " );
         // Get Session object in 
        the TestServlet = User (the TestServlet) Request.getSession () the getAttribute (. " Userobj " );
         OUT .println ( " <h1> successful landing </ h1> " );
         OUT .println ( " <a href='/user/Loin'> return to re-visit </a> " );
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

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