學習完java基礎後，自己練了練用MySql作為數據存儲的簡單用戶管理系統，這是一個沒有界面的管理系統，看起來比較枯燥，先給出幾張截圖吧。

首先預覽一下包結構吧

主類是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){
            //顯示內容
            menu.showInfro();
            Item item=menu.pickItem();
            menu=item.excute();
        }
        System.out.println("謝謝使用，再見，拜拜！");
    }
}
 

用兩個接口來規範

第一個是菜單接口，抽象了兩個抽象方法，

package com.nensoft.bean;

public interface Menu {

    //顯示菜單
    void showInfro();
    //提供選項（對象)
    Item pickItem();
}

第二個是，菜單項接口，抽象的是菜單執行的方法

public interface Item {

    //執行功能
    Menu excute();
}

UserInfo是用來記錄當前用戶信息的

package com.nensoft.bean;
//實體類entity
public class Userinfo {

    private int id;
    private String username;
    private String password;
    private String email;
    private int power;
    //無參構造器與框架有關
    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包

權限分為普通用戶菜單（NormalMenu）和管理員菜單(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 showInfro() {
        // TODO Auto-generated method stub
        System.out.println("==============");
        System.out.println("歡迎登錄主窗體！");
        System.out.println(Start.loginuser.getUsername()+" 您好！        "+"您的權限是：管理員");
        System.out.println("添加用戶---------1");
        System.out.println("刪除用戶---------2");
        System.out.println("修改用戶---------3");
        System.out.println("查詢用戶---------4");
        System.out.println("退出程序---------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("歡迎登錄主窗體！");
        System.out.println(Start.loginuser.getUsername()+" 您好！        "+"您的權限是：普通用戶");
        System.out.println("修改自己的信息---------1");
        System.out.println("查詢自己的信息---------2");
        System.out.println("退出程序--------------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;
    }

}

還有一個主菜單，用於顯示登錄界面的

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("歡迎使用neusoft用戶管理系統");
        System.out.println("===================");
        System.out.println("用戶登錄===========1");
        System.out.println("用戶註冊===========2");
        System.out.println("用戶退出===========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;
    }

}

另外一個是管理員的查詢菜單

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("查詢所有用戶--------1");
        System.out.println("查詢單個用戶--------2");
        System.out.println("返回--------------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;
    }

}

有一個工具類，包括數據庫的連接，以及對用戶輸入數據的檢測是否規範，com.util包

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.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    public void close(PreparedStatement item){
        if(item!=null){
            try {
                item.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
    }
}

工具類

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("請選擇");
            try{
                int num=scan.nextInt();
                if(num<low || num> high){
                    System.out.println("數值非法，重新選擇");
                }else{
                    return num;
                }
            }catch(Exception e){
                
            }
        }
    }
    public static String getString(){
        while(true){
            Scanner scan=new Scanner(System.in);
            //System.out.println("請選擇");
            String str=scan.nextLine();
            if(str !=null && str.trim()!=""){
                return str;
            }else{
                System.out.println("錯誤");
            }
        }
    }
    public static String getEmail(){
        while(true){
            Scanner scan=new Scanner(System.in);
            String email=scan.nextLine();
            /*
             * 必須有@
             * 不能有多個@和。
             * @不能在.前面
             * @不能開頭，。不能結尾
             */
            if(email.indexOf("@") ==-1|| email.indexOf(".")==-1){
                System.out.println("郵箱中必須有@和.");
            }else if(email.indexOf("@") != email.lastIndexOf("@") || email.indexOf(".")!=
                    email.lastIndexOf(".")){
                System.out.println("郵箱中不能有多個@和.");
            }else if(email.startsWith("@")  || email.endsWith(".")){
                System.out.println("郵箱中不能@開頭和.結尾");
            }else{
                return email;
            }
        }
    }
    
}

主菜單包下包括用戶登錄類，註冊類，

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("用戶登錄界面");
        System.out.println("==============");
        System.out.println("請輸入你的用戶名：");
        String username= ConsoleUtil.getString();
        System.out.println("請輸入你的密碼：");
        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("登錄成功");
                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.printStackTrace();
        }
        return (Menu) new MainMenu();
    }

}

註冊類

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
        System.out.println("用戶註冊界面");
        System.out.println("==========");
        System.out.println("請輸入你的用戶名");
        String username=ConsoleUtil.getString();
        System.out.println("請輸入你的密碼：");
        String password = ConsoleUtil.getString();
        System.out.println("請輸入你的郵箱：");
        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("此用戶已被占用");
            }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("註冊成功!");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return new MainMenu();
    }

}

普通用戶菜單項包com.normalusermenu

修改本人的信息

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("您現在的信息是：");
        System.out.println(Start.loginuser.getId()+"  |  "+Start.loginuser.getUsername()+"  |  " +
                Start.loginuser.getPassword()+"  |  "+Start.loginuser.getEmail()+"  |  "+
                (Start.loginuser.getPower()==0?"普通用戶":"管理員"));
        System.out.println("================");
        System.out.println("請輸入您要修改的姓名：");
        String username=ConsoleUtil.getString();
        System.out.println("請輸入您要修改的密碼：");
        String password=ConsoleUtil.getString();
        System.out.println("請輸入您要修改的郵箱：");
        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("用戶名已被占用！  請重新輸入...");
                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);  //修改完數據庫的信息後還要同時修改用戶類(UserInfo)的屬性
                Start.loginuser.setPassword(password);
                Start.loginuser.setEmail(email);
                System.out.println("修改成功!");
                
            }
            
        } 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();
    }

}

查詢個人信息

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("您現在的信息是：");
        System.out.println(Start.loginuser.getId()+"  |  "+Start.loginuser.getUsername()+"  |  " +
                Start.loginuser.getPassword()+"  |  "+Start.loginuser.getEmail()+"  |  "+
                (Start.loginuser.getPower()==0?"普通用戶":"管理員"));
        return new NormalMenu();
    }

}

這裏只列出了部分主要代碼，要查看全部代碼請到我的Coding裏去看

java開發簡單的用戶管理系統