package demo;

import java.sql.*;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class JDBC {

public Connection connect() throws ClassNotFoundException, SQLException{

? ? Connection conn=null;?

? ? Class.forName("com.mysql.jdbc.Driver");

? ? String url = "jdbc:mysql://47.122.1.22/pzj_users?"

? ? ? ? ? ? ? ? + "user=root_user&password=pzj2020@&useUnicode=true&characterEncoding=UTF8";

conn=DriverManager.getConnection(url);?

return conn;

}

public void close(Statement stat,Connection conn) throws SQLException{

if(stat!=null){

? ? ? ?stat.close();

? ? }

? ? if(conn!=null){

? ? ? ?conn.close();? ? ?

? ? }

}

public int insert(HttpServletRequest request, HttpServletResponse response) throws ClassNotFoundException, SQLException{

? ? Connection conn=null;

? ? Statement stat=null;

? ? ? ? String name=request.getParameter("name");

? ? ? ? String password=request.getParameter("password");? ??

conn=connect();

stat=conn.createStatement();

int i=stat.executeUpdate("insert into shule_user values('"+name+"','"+password+"')");?

? ? close(stat,conn);

? ? return i;

? ? }

public int delete(HttpServletRequest request, HttpServletResponse response) throws ClassNotFoundException, SQLException{

? ? Connection conn=null;

? ? Statement stat=null;

? ? ? ? String name=request.getParameter("name");

conn=connect();

stat=conn.createStatement();

int i=stat.executeUpdate("delete from shule_user where name ='"+name+"'");

? ? close(stat,conn);

? ? return i;

? ? }

public int change(HttpServletRequest request, HttpServletResponse response) throws ClassNotFoundException, SQLException{

? ? Connection conn=null;

? ? Statement stat=null;

? ? ? ? String name=request.getParameter("name");

? ? ? ? String password=request.getParameter("password");

conn=connect();

stat=conn.createStatement();

int i=stat.executeUpdate("update shule_user set password='"+password+"' where name ='"+name+"'");

? ? close(stat,conn);

? ? return i;

? ? }

public String view(HttpServletRequest request, HttpServletResponse response) throws ClassNotFoundException, SQLException{

? ? Connection conn=null;

? ? Statement stat=null;

? ? ResultSet rs=null;

? ? conn=connect();

stat=conn.createStatement();

? ? String Data="";

? ? ? ? ?rs=stat.executeQuery("select * from shule_user");?

? ? while(rs.next())

? ? ? ? {

? ? Data+=rs.getString("name")+" "+rs.getString("password")+" "+"\n";

? ? ? ? }

? ? if(rs!=null){

? ? ? rs.close();

? ? ? ?}

? ? close(stat,conn);

? ? return Data;

? ? }

}