Java to develop a simple user management system

After learning the basics of Java, I practiced using MySQL as a simple user management system for data storage, this is a management system without interface, it looks more boring, first give a few bar.

Let's start by previewing the package structure.

The main class is Start.java

import com.menu.MainMenu;import com.nensoft.bean.Item;import com.nensoft.bean.Menu;import com.nensoft.bean.Userinfo;import com.utils.DBUtil2;public class Start {    public static Userinfo loginuser=new Userinfo();    public static DBUtil2 db=DBUtil2.getInstance();    public static void main(String[] args) {        // TODO Auto-generated method stub        Menu menu=new MainMenu();        while(menu != null){            //显示内容            menu.showInfro();            Item item=menu.pickItem();            menu=item.excute();        }        System.out.println("谢谢使用，再见，拜拜！");    }}

Use two interfaces to standardize

The first one is the menu interface, which abstracts two abstract methods,

package com.nensoft.bean;public interface Menu {    //显示菜单    void showInfro();    //提供选项（对象)    Item pickItem();}

The second is, the menu item interface, the abstract is the method of the menus execution

public interface Item {    //执行功能    Menu excute();}

UserInfo is used to record the current user information

Package com.nensoft.bean;//entity Class Entitypublic class Userinfo {private int id;    Private String username;    private String password;    Private String Email;    private int power;  The parameterless constructor is related to the framework public Userinfo () {} public Userinfo (int ID, string username, string password, string email,        int power) {super ();        This.id = ID;        This.username = Username;        This.password = password;        This.email = email;    This.power = power;    } public int getId () {return id;    } public void setId (int id) {this.id = ID;    } public String GetUserName () {return username;    } public void Setusername (String username) {this.username = username;    } public String GetPassword () {return password;    } public void SetPassword (String password) {this.password = password;    } public String Getemail () {return email; } public void Setemail (String email) {This.email = email;    } public int Getpower () {return power;    } public void Setpower (int power) {this.power = power; }    }

Com. Menu Package

Permissions are divided into normal user menu (Normalmenu) and Administrator menu (Adminmenu)

Import Com.adminmenuitem.adduser;import Com.adminmenuitem.deleteuser;import Com.adminmenuitem.modifyuser;import Com.adminmenuitem.serchuser;import Com.mainmenuitem.exit;import Com.nensoft.bean.item;import Com.nensoft.bean.menu;import Com.nensoft.start.start;import Com.normalmenu.modifyselfinfo;import Com.normalmenu.serchselfinfo;import Com.utils.consoleutil;public class Adminmenu implements menu{public void SHOWINFR        O () {//TODO auto-generated Method Stub System.out.println ("=============="); System.out.println ("Welcome to the main form!")        ");        System.out.println (Start.loginuser.getUsername () + "Hello!"        "+" your permission is: Administrator ");        System.out.println ("Add user---------1");        System.out.println ("Delete user---------2");        SYSTEM.OUT.PRINTLN ("Modify user---------3");        SYSTEM.OUT.PRINTLN ("Query user---------4");            System.out.println ("Exit program---------5");        } public Item Pickitem () {//TODO auto-generated method stub Item item=null; int Option=consoleutil. getOption (1, 5);            Switch (option) {case 1:item=new AddUser ();        Break            Case 2:item=new DeleteUser ();        Break            Case 3:item=new ModifyUser ();        Break            Case 4:item=new Serchuser ();        Break            Case 5:item=new Exit ();        Break    } return item; }}

Import Com.mainmenuitem.exit;import Com.nensoft.bean.item;import Com.nensoft.bean.menu;import Com.nensoft.start.start;import Com.normalmenu.modifyselfinfo;import Com.normalmenu.serchselfinfo;import Com.utils.consoleutil;public class Normalmenu implements menu{public void Showinfro () {//TODO auto-generated        Method Stub System.out.println ("=============="); System.out.println ("Welcome to the main form!")        ");        System.out.println (Start.loginuser.getUsername () + "Hello!"        "+" your permission is: Ordinary user ");        SYSTEM.OUT.PRINTLN ("Modify your own information---------1");        SYSTEM.OUT.PRINTLN ("Query your own information---------2");    System.out.println ("Exit program--------------3");        } public Item Pickitem () {//TODO auto-generated method stub Item item=null;        int Option=consoleutil.getoption (1, 3);            Switch (option) {case 1:item=new modifyselfinfo ();        Break            Case 2:item=new Serchselfinfo ();        Break Case 3:item=new Exit ();       } return item; }}

There is also a main menu for displaying the login interface

import com.mainmenuitem.Exit;import com.mainmenuitem.LoginItem;import com.mainmenuitem.RegItem;import com.nensoft.bean.Item;import com.nensoft.bean.Menu;import com.utils.ConsoleUtil;public class MainMenu implements Menu{    public void showInfro() {        // TODO Auto-generated method stub        System.out.println("欢迎使用neusoft用户管理系统");        System.out.println("===================");        System.out.println("用户登录===========1");        System.out.println("用户注册===========2");        System.out.println("用户退出===========3");            }    public Item pickItem() {        // TODO Auto-generated method stub        Item item=null;        //        int option =ConsoleUtil.getOption(1, 3);        switch(option){        case 1:            item=new LoginItem();            break;                    case 2:            item =new RegItem();            break;        case 3:            item=new Exit();        }        return item;    }}

Another is the administrator's query menu

Import Com.adminmenuitem.returnmenu;import Com.adminmenuitem.serchuser;import Com.mainmenuitem.exit;import Com.mainmenuitem.loginitem;import Com.mainmenuitem.regitem;import Com.nensoft.bean.item;import Com.nensoft.bean.menu;import Com.serchuser_item. Serchalluser;import Com.serchuser_item.        Serchoneuser;import Com.utils.consoleutil;public class Serchusermenu implements menu{public void Showinfro () {        TODO auto-generated Method Stub System.out.println ("============");        SYSTEM.OUT.PRINTLN ("Query all Users--------1");        SYSTEM.OUT.PRINTLN ("Query single user--------2");    System.out.println ("Return--------------3");        } public Item Pickitem () {//TODO auto-generated method stub Item item=null;        int option =consoleutil.getoption (1, 3);            Switch (option) {case 1:item=new serchalluser ();                    Break            Case 2:item =new serchoneuser ();        Break Case 3:item=new ReturnMenu ();    } return item; }}

There is a tool class, including database connection, and the detection of user input data specification, Com.util package

Package Com.utils;import Java.io.ioexception;import Java.sql.connection;import java.sql.drivermanager;import Java.sql.preparedstatement;import Java.sql.resultset;import Java.sql.sqlexception;import Java.text.Format;import    Java.util.properties;public class DBUtil2 {private static DBUTIL2 db;    Private String URL;    Private String username;    private String password;    Private String driver;        Private DBUtil2 () {Properties Properties=new properties ();            try {properties.load (This.getclass (). getClassLoader (). getResourceAsStream ("db.properties"));            Driver=properties.getproperty ("Driver");            Url=properties.getproperty ("url");            Username=properties.getproperty ("username");        Password=properties.getproperty ("password");        } catch (IOException e) {//TODO auto-generated catch block E.printstacktrace (); }} public static DBUtil2 getinstance () {if (db==null) {db = new dbUtil2 ();    } return DB;        } public Connection GetConnect () {try {class.forname ("com.mysql.jdbc.Driver");        } catch (ClassNotFoundException e) {//TODO auto-generated catch block E.printstacktrace ();        } Connection Conn=null;        try {conn = drivermanager.getconnection (Url,username,password);        } catch (SQLException e) {//TODO auto-generated catch block E.printstacktrace ();    } return conn;            public void Close (Connection item) {if (item!=null) {try {item.close ();            } catch (SQLException e) {//TODO auto-generated catch block E.printstacktrace (); }}} public void Close (ResultSet item) {if (item!=null) {try {Item.clos            E ();                } catch (SQLException e) {//TODO auto-generated catch blockE.printstacktrace (); }}} public void Close (PreparedStatement item) {if (item!=null) {try {item.            Close ();            } catch (SQLException e) {//TODO auto-generated catch block E.printstacktrace (); }        }            }}

Tool class

Package Com.utils;import Java.util.scanner;public class Consoleutil {public static int getOption (Int. Low,int High) {            while (true) {Scanner scan=new Scanner (system.in);            SYSTEM.OUT.PRINTLN ("Please select");                try{int num=scan.nextint ();                if (Num<low | | num> high) {System.out.println ("value is illegal, re-select");                }else{return num; }}catch (Exception e) {}}} public static String getString () {W            Hile (True) {Scanner scan=new Scanner (system.in);            SYSTEM.OUT.PRINTLN ("Please select");            String Str=scan.nextline ();            if (str!=null && str.trim ()! = "") {return str;            }else{System.out.println ("error");            }}} public static String Getemail () {while (true) {Scanner scan=new Scanner (system.in); String EMAIl=scan.nextline ();             /* * Must have @ * cannot have multiple @ and. * Cannot start at. Front * @ cannot begin,. Cannot end */if (Email.indexof ("@") ==-1| | email.indexof (".")            ==-1) {System.out.println ("must have @ and." in the mailbox); }else if (Email.indexof ("@")! = Email.lastindexof ("@") | | email.indexof (".")! = Email.lastindexof ("."))            {SYSTEM.OUT.PRINTLN ("cannot have more than one @ and." in the mailbox); }else if (Email.startswith ("@") | | | Email.endswith ("."))            {System.out.println ("Cannot start and end in mailbox");            }else{return email; }        }    }    }

The main Menu package includes the user login class, the registration class,

Package Com.mainmenuitem;import Java.sql.connection;import Java.sql.preparedstatement;import java.sql.ResultSet; Import Java.sql.sqlexception;import com.menu.adminmenu;import Com.menu.mainmenu;import Com.menu.NormalMenu;import Com.nensoft.bean.item;import Com.nensoft.bean.menu;import Com.nensoft.bean.userinfo;import Com.nensoft.start.start;import Com.utils.consoleutil;import Com.utils.dbutil2;public class LoginItem implements Item        {public Menu Excute () {//TODO auto-generated Method Stub System.out.println ("User login Interface");        System.out.println ("==============");        System.out.println ("Please enter your user name:");        String username= consoleutil.getstring ();        System.out.println ("Please enter your password:");        String password= consoleutil.getstring ();        Connection Con=start.db.getconnect ();        PreparedStatement Ps=null;            try {ps=con.preparestatement ("select * from UserInfo where username=?");            Ps.setstring (1, username); ResultSet st=pS.executequery ();                if (St.next ()) {Userinfo userinfo=new Userinfo ();                Userinfo.setid (St.getint ("id"));                Userinfo.setusername (st.getstring (2));                Userinfo.setpassword (St.getstring (3));                Userinfo.setemail (St.getstring (4));                Userinfo.setpower (St.getint (5));                SYSTEM.OUT.PRINTLN ("Login Successful");                Start.loginuser=userinfo;                if (userinfo.getpower () = = 0) {return (Menu) new Normalmenu ();                }else{return (Menu) new Adminmenu (); }}} catch (SQLException e) {//TODO auto-generated catch block E.printstacktrac        E ();    } return (Menu) new MainMenu (); }}

Registering classes

Package Com.mainmenuitem;import Java.sql.connection;import Java.sql.preparedstatement;import java.sql.ResultSet; Import Java.sql.sqlexception;import com.menu.mainmenu;import com.nensoft.bean.item;import com.nensoft.bean.Menu; Import Com.nensoft.start.start;import com.utils.consoleutil;import com.utils.dbutil;import com.utils.DBUtil2; public class Regitem implements item{public Menu Excute () {//TODO auto-generated method Stub syste        M.OUT.PRINTLN ("User Registration Interface");        System.out.println ("==========");        System.out.println ("Please enter your user name");        String username=consoleutil.getstring ();        System.out.println ("Please enter your password:");        String password = consoleutil.getstring ();        System.out.println ("Please enter your e-mail:");        String email= Consoleutil.getemail ();        Connection Con=start.db.getconnect ();        PreparedStatement Ps=null;            try {ps=con.preparestatement ("select * from UserInfo where username=?");           Ps.setstring (1, username); ResultSet St=ps.executequery ();                if (St.next ()) {System.out.println (ST);            SYSTEM.OUT.PRINTLN ("This user has been occupied");                }else{ps=con.preparestatement ("INSERT into userinfo (Username,password,email) VALUES (?,?,?)");                Ps.setstring (1, username);                Ps.setstring (2, password);                Ps.setstring (3, email);                Ps.executeupdate ();                Con.setautocommit (TRUE);            SYSTEM.OUT.PRINTLN ("Registered successfully!");        }} catch (SQLException e) {//TODO auto-generated catch block E.printstacktrace ();    } return new MainMenu (); }}

Normal User menu item package Com.normalusermenu

Modify my Information

Package Com.normalmenu;import Java.sql.connection;import Java.sql.preparedstatement;import java.sql.ResultSet; Import Java.sql.sqlexception;import com.menu.normalmenu;import com.nensoft.bean.item;import com.nensoft.bean.Menu; Import Com.nensoft.start.start;import Com.utils.consoleutil;import Com.utils.dbutil2;public class ModifySelfInfo Implements item{public Menu Excute () {//TODO auto-generated Method Stub System.out.println ("======        ==========");        System.out.println ("Your present information is:");  System.out.println (Start.loginuser.getId () + "|  "+start.loginuser.getusername () +" |  "+ Start.loginuser.getPassword () +" |  "+start.loginuser.getemail () +" | "+ (Start.loginuser.getPower () ==0?"        Normal user ":" Administrator "));        System.out.println ("================");        System.out.println ("Please enter the name you want to modify:");        String username=consoleutil.getstring ();        System.out.println ("Please enter the password you want to modify:");        String password=consoleutil.getstring (); SysteM.out.println ("Please enter the mailbox you want to edit:");        String email=consoleutil.getstring ();        Connection Conn=start.db.getconnect ();        PreparedStatement Ps=null;                ResultSet Rs=null; try {ps=conn.preparestatement ("select * from UserInfo where username=?")            and id!=? ");            Ps.setstring (1, username);            Ps.setint (2,start.loginuser.getid ());            Rs=ps.executequery ();  if (Rs.next ()) {System.out.println ("username is already occupied!                Please re-enter ... ");            Username=consoleutil.getstring ();                }else{Conn.setautocommit (FALSE); Ps=conn.preparestatement ("Update userinfo set username=?,password=?,email=?")                where id= "+start.loginuser.getid ());                Ps.setstring (1,username);                Ps.setstring (2, password);                Ps.setstring (3, email);                Ps.executeupdate ();                Conn.commit ();  Start.loginuser.setUsername (username); After you modify the database information, you also modify the user classInfo) attribute Start.loginuser.setPassword (password);                Start.loginuser.setEmail (email);                            SYSTEM.OUT.PRINTLN ("Modified successfully!"); }} catch (SQLException e) {//TODO auto-generated catch block E.printstacktrace        ();        } Start.db.close (RS);        Start.db.close (PS);        Start.db.close (conn);    return new Normalmenu (); }}

Search for personal information

package com.normalmenu;import com.menu.NormalMenu;import com.nensoft.bean.Item;import com.nensoft.bean.Menu;import com.nensoft.start.Start;public class SerchSelfInfo implements Item{    public Menu excute() {        // TODO Auto-generated method stub        System.out.println("================");        System.out.println("您现在的信息是：");        System.out.println(Start.loginuser.getId()+"  |  "+Start.loginuser.getUsername()+"  |  " +                Start.loginuser.getPassword()+"  |  "+Start.loginuser.getEmail()+"  |  "+                (Start.loginuser.getPower()==0?"普通用户":"管理员"));        return new NormalMenu();    }}

Here are only some of the main code, to see all the code please go to my coding to see

Java to develop a simple user management system