JDBC项目练习，用户管理系统（分层实现）

开发环境：JDK8.0，Eclipse 4.3，Mysql

源码（包括sql文件）：https://download.csdn.net/download/mistywood/11647743
https://github.com/MistyWood/proJDBC/tree/master

（注意：第一位管理员需手动添加到数据库，记得加载mysql驱动）

软件功能：

1.注册功能：用户可以注册成本软件的用户。（注：权限是普通用户）

2.登录功能：用户输入用户名和密码，判断用户是否存在，提取用户的权限

权限如果是管理员则显示：

权限如果是普通用户则显示：

3.普通用户的修改功能，普通用户可以修改自己的姓名，密码，邮箱，不能修改权限和ID。

运行效果如下图:

4.普通用户的查询功能

普通用户可以查询自己的所有详细信息

5.管理员的添加功能

管理员的添加和普通用户的注册一样，id 自动分配。添加的新用户权限是管理员

6.管理员的修改功能

管理员可以根据id修改修改任何人的信息。（注：可以把普通用户修改成管理员）

7.管理员的查询功能

有三种方式
查询全部人员

按id查询

按姓名查询（支持模糊查询）

8.管理员的删除功能

工作流程图：

项目实现

1.首先创建数据库

根据题意，数据库里的user表中有id（流水号），username（姓名），pwd（密码），email（邮箱），admin（用户权限）几个字段

2.建立db包，用DBUtils类连接数据库

package com.cyz.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DBUtils {

	private static String drive = "org.gjt.mm.mysql.Driver";
	private static String url = "jdbc:mysql://localhost/projdbc?&useUnicode=true&characterEncoding=utf-8";
	private static String user = "root";
	private static String password = "root123";

	static {
		try {
			Class.forName(drive);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	private DBUtils() {
	}

	public static Connection getConn() throws SQLException {
		return DriverManager.getConnection(url, user, password);
	}

	public static void close(ResultSet rs, PreparedStatement pstm, Connection conn) {
		try {
			if (rs != null) {
				rs.close();
			}
			if (pstm != null) {
				pstm.close();
			}
			if (conn != null) {
				conn.close();
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}

3.根据数据库创建实体类

package com.cyz.dao;

public class User {
	private int id;
	private String username;
	private String pwd;
	private String email;
	private String admin;
	public User(String username, String pwd, String email) {
		super();
		this.username = username;
		this.pwd = pwd;
		this.email = email;
	}
	public User(int id, String username, String pwd, String email, String admin) {
		super();
		this.id = id;
		this.username = username;
		this.pwd = pwd;
		this.email = email;
		this.admin = admin;
	}
	public User(String username, String pwd, String email, String admin) {
		super();
		this.username = username;
		this.pwd = pwd;
		this.email = email;
		this.admin = admin;
	}
	
	public User(int id, String username, String pwd, String email) {
		super();
		this.id = id;
		this.username = username;
		this.pwd = pwd;
		this.email = email;
	}
	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 getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getAdmin() {
		return admin;
	}
	public void setAdmin(String admin) {
		this.admin = admin;
	}

}

4.接下来开始写model-view-controller层

view层，即视图界面

主界面MainView.java

package com.cyz.view;

import java.util.Scanner;

public class MainView {
	static Scanner sc = new Scanner(System.in);

	public static void run() {

		while (true) {
			System.out.println("==========================");
			System.out.println("欢迎使用用户管理系统");
			System.out.println("==========================");
			System.out.println("用户登录---------1");
			System.out.println("用户注册---------2");
			System.out.println("退出程序---------3");
			String option = sc.nextLine();
			switch (option) {
			case "1":
				LoginView.show();
				break;
			case "2":
				RegisterView.show();
				break;
			case "3":
				return;
			default:
				System.out.println("请重新输入");
				break;
			}
		}
	}

}

注册界面RegisterView.java

package com.cyz.view;

import java.util.Scanner;

import com.cyz.dao.User;
import com.cyz.service.UserService;
import com.cyz.service.UserServiceImpl;

public class RegisterView {

	static Scanner sc = new Scanner(System.in);

	public static void show() {
		System.out.println("用户注册界面");
		System.out.println("==========================");
		System.out.println("请输入您的用户名");
		String username = sc.nextLine();
		System.out.println("请输入您的密码");
		String pwd = sc.nextLine();
		System.out.println("请输入您的邮箱");
		String email = sc.nextLine();

		User u = new User(username, pwd, email,"普通用户");
		UserService us = new UserServiceImpl();
		if (us.register(u))
			System.out.println("用户注册成功，请重新登录");
		else
			System.out.println("用户名已存在或为空，用户注册失败");
		return;

	}

}

登录界面Login.java

package com.cyz.view;

import java.util.Scanner;

import com.cyz.service.UserService;
import com.cyz.service.UserServiceImpl;

public class LoginView {

	static Scanner sc = new Scanner(System.in);

	// 登录界面
	public static void show() {

		System.out.println("==========================");
		System.out.println("用户登录界面");
		System.out.println("==========================");
		System.out.println("请输入您的用户名");
		String username = sc.nextLine();
		System.out.println("请输入您的密码");
		String pwd = sc.nextLine();

		UserService us = new UserServiceImpl();
		us.login(username, pwd);
		return;
	}

}

普通用户操作界面UserView.java

package com.cyz.view;

import java.util.Scanner;

import com.cyz.dao.User;
import com.cyz.service.UserService;
import com.cyz.service.UserServiceImpl;

public class UserView {
	static Scanner sc = new Scanner(System.in);

	// 普通用户登录之后的主界面
	public static void show(User u) {

		System.out.println("==========================");
		System.out.println("欢迎登录主窗体");
		System.out.println(u.getUsername() + " 您好，您的权限是：普通用户");

		while (true) {
			System.out.println("==========================");
			System.out.println("修改自己的信息---------1");
			System.out.println("查询自己的信息---------2");
			System.out.println("返回上一级--------------3");
			String option = sc.nextLine();
			switch (option) {
			case "1":
				UserView.userModifyShow(u);
				break;
			case "2":
				UserView.userInfoShow(u);
				break;
			case "3":
				return;
			default:
				System.out.println("请重新输入");
				break;
			}
		}
	}

	// 普通用户修改个人信息界面
	public static void userModifyShow(User u) {
		System.out.println("您现在的信息是：");
		System.out.println(
				u.getId() + " " + u.getUsername() + " " + u.getPwd() + " " + u.getEmail() + " " + u.getAdmin());
		System.out.println("==========================");

		System.out.println("请输入要修改的姓名");
		String username = sc.nextLine();
		u.setUsername(username);
		System.out.println("请输入要修改的密码");
		String pwd = sc.nextLine();
		u.setPwd(pwd);
		System.out.println("请输入要修改的邮箱");
		String email = sc.nextLine();
		u.setEmail(email);
		
		UserService us = new UserServiceImpl();
		us.userModify(u);

	}

	// 用户查询个人信息
	public static void userInfoShow(User u) {
		UserService us = new UserServiceImpl();
		User user = us.userInfo(u.getUsername());
		System.out.println(user.getId() + "\t" + user.getUsername() + "\t" + user.getPwd() + "\t" + user.getEmail()
				+ "\t" + user.getAdmin());
		return;
	}

}

管理员操作界面

package com.cyz.view;

import java.util.Iterator;
import java.util.List;
import java.util.Scanner;

import com.cyz.dao.User;
import com.cyz.service.UserService;
import com.cyz.service.UserServiceImpl;

public class AdminView {
	
	static Scanner sc = new Scanner(System.in);
	
	// 管理员登录过后的主界面
	public static void show(User u) {

		System.out.println("==========================");
		System.out.println("欢迎登录主窗体");
		System.out.println(u.getUsername() + " 您好，您的权限是：管理员");

		while (true) {
			System.out.println("==========================");
			System.out.println("添加用户--------------1");
			System.out.println("删除用户--------------2");
			System.out.println("修改用户--------------3");
			System.out.println("查询用户--------------4");
			System.out.println("返回上一级------------5");
			String option = sc.nextLine();
			switch (option) {
			case "1":
				AdminView.adminAddUserShow();
				break;
			case "2":
				AdminView.delUserShow();
				break;
			case "3":
				AdminView.adminModifyShow();
				break;
			case "4":
				AdminView.adminQueryShow();
				break;
			case "5":
				return;
			default:
				System.out.println("请重新输入");
				break;
			}
		}
	}

	// 管理员添加用户
	public static void adminAddUserShow() {
		System.out.println("==========================");
		System.out.println("用户添加界面");
		System.out.println("==========================");
		System.out.println("请输入添加的用户名");
		String username = sc.nextLine();
		System.out.println("请输入添加的密码");
		String pwd = sc.nextLine();
		System.out.println("请输入添加的邮箱");
		String email = sc.nextLine();

		User u = new User(username, pwd, email,"管理员");
		UserService us = new UserServiceImpl();
		if (us.register(u))
			System.out.println("用户添加成功");
		else
			System.out.println("用户名已存在或为空，用户添加失败");
		return;
	}

	// 管理员删除用户
	private static void delUserShow() {

		System.out.println("请输入要删除用户的ID号码");
		int id=Integer.parseInt(sc.nextLine());
		UserService us = new UserServiceImpl();
		us.delUser(id);
		return;
	}

	// 管理员修改用户
	private static void adminModifyShow() {

		System.out.println("请输入要修改的用户的ID号码");
		int id = Integer.parseInt(sc.nextLine());
		System.out.println("请输入要修改的用户的用户名");
		String username = sc.nextLine();
		System.out.println("请输入要修改的用户的密码");
		String pwd = sc.nextLine();
		System.out.println("请输入要修改的用户的邮箱");
		String email = sc.nextLine();
		System.out.println("请输入要修改的用户的权限（管理员/普通用户）");
		String admin = sc.nextLine();

		User u = new User(id, username, pwd, email, admin);
		UserService us = new UserServiceImpl();
		us.adminModifyUser(u);

	}


	// 管理员查询用户
	public static void adminQueryShow() {

		while (true) {
			System.out.println("查询全部用户--------------1");
			System.out.println("根据id查询用户--------------2");
			System.out.println("根据姓名查询用户--------------3");
			System.out.println("返回上一级--------------4");
			String option = sc.nextLine();
			switch (option) {
			case "1":
				AdminView.adminQueryAllShow();
				break;
			case "2":
				AdminView.adminQueryByIdShow();
				break;
			case "3":
				AdminView.adminQueryByNameShow();
				break;
			case "4":
				return;
			default:
				System.out.println("请重新输入");
				break;
			}
		}

	}
	
	// 管理员查询所有用户
	public static void adminQueryAllShow() {
		UserService us = new UserServiceImpl();
		List users = us.queryAll();
		if(users.size()==0) System.out.println("查询结果为空\n");
		Iterator it = users.iterator();
		while(it.hasNext()) {
			User user=it.next();
			System.out.println(user.getId() + "\t" + user.getUsername() + "\t" + user.getPwd() + "\t" + user.getEmail() + "\t"
					+ user.getAdmin());
			System.out.println("================================================");
		}
		return;
	}
	
	// 管理员按id查询用户
	public static void adminQueryByIdShow() {
		System.out.println("请输入要查询的id");
		int id=Integer.parseInt(sc.nextLine());
		UserService us = new UserServiceImpl();
		User u=us.queryById(id);
		if(u!=null) {
			System.out.println(u);
		}else {
			System.out.println("用户不存在");
		}
		System.out.println("================================================");
		return;
	}
	
	// 管理员按username查询用户(支持模糊查询)
	public static void adminQueryByNameShow() {
		
		System.out.println("请输入要查询的名字（支持模糊查询）");
		String name=sc.nextLine();
		UserService us = new UserServiceImpl();
		List users=us.queryByName(name);
		if(users.size()==0) System.out.println("查询结果为空\n");
		Iterator it = users.iterator();
		while(it.hasNext()) {
			User user=it.next();
			System.out.println(user);
			System.out.println("================================================");
		}
		return;
	}
	

}

model层，即数据库基本操作

写了UserDao接口，用UserDaoImpl实现，此处UserDao略去不写

package com.cyz.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.cyz.db.DBUtils;

public class UserDaoImpl implements UserDao {

	@Override
	public boolean addUser(User u) {
		Connection conn=null;
		PreparedStatement pstm=null;
		try {
			conn=DBUtils.getConn();
			String sql=" insert into user(username,pwd,email,admin) value(?,?,?,?) ";
			pstm=conn.prepareStatement(sql);
			pstm.setString(1, u.getUsername());
			pstm.setString(2, u.getPwd());
			pstm.setString(3, u.getEmail());
			pstm.setString(4, u.getAdmin());
			return pstm.executeUpdate()>0;
		} catch (SQLException e) {
			System.out.println("注册添加失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(null, pstm, conn);
		}
		return false;
	}

	@Override
	public boolean modifyUser(User u) {
		Connection conn=null;
		PreparedStatement pstm=null;
		try {
			conn=DBUtils.getConn();
			String sql=" update user set username=?,pwd=?,email=?,admin=? where id=? ";
			pstm=conn.prepareStatement(sql);
			pstm.setString(1, u.getUsername());
			pstm.setString(2, u.getPwd());
			pstm.setString(3, u.getEmail());
			pstm.setString(4, u.getAdmin());
			pstm.setInt(5, u.getId());
			return pstm.executeUpdate()>0;
		} catch (SQLException e) {
			System.out.println("修改信息失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(null, pstm, conn);
		}
		return false;
	}

	@Override
	public User queryByNameAndPwd(String username, String pwd) {
		Connection conn=null;
		PreparedStatement pstm=null;
		ResultSet rs=null;
		User u=null;
		try {
			conn=DBUtils.getConn();
			String sql=" select id,username,pwd,email,admin from user where username=? and pwd=?";
			pstm=conn.prepareStatement(sql);
			pstm.setString(1, username);
			pstm.setString(2, pwd);
			rs=pstm.executeQuery();
			while(rs.next()) {
				u=new User(rs.getInt("id"),rs.getString("username"),rs.getString("pwd"),rs.getString("email"),rs.getString("admin")); 
			}
			return u;
		} catch (SQLException e) {
			System.out.println("查询失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(rs, pstm, conn);
		}
		return null;
	}

	@Override
	public User queryByUsername(String username) {
		Connection conn=null;
		PreparedStatement pstm=null;
		ResultSet rs=null;
		User u=null;
		try {
			conn=DBUtils.getConn();
			String sql=" select id,username,pwd,email,admin from user where username=? ";
			pstm=conn.prepareStatement(sql);
			pstm.setString(1, username);
			rs=pstm.executeQuery();
			while(rs.next()) {
				u=new User(rs.getInt("id"),rs.getString("username"),rs.getString("pwd"),rs.getString("email"),rs.getString("admin")); 
			}
			return u;
		} catch (SQLException e) {
			System.out.println("查询失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(rs, pstm, conn);
		}
		return null;
	}

	@Override
	public boolean delUser(int id) {
		
		Connection conn=null;
		PreparedStatement pstm=null;
		try {
			conn=DBUtils.getConn();
			String sql=" delete from user where id=? ";
			pstm=conn.prepareStatement(sql);
			pstm.setInt(1, id);
			return pstm.executeUpdate()>0;
		} catch (SQLException e) {
			System.out.println("删除失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(null, pstm, conn);
		}
		return false;
	}

	@Override
	public User queryById(int id) {
		Connection conn=null;
		PreparedStatement pstm=null;
		ResultSet rs=null;
		User u=null;
		try {
			conn=DBUtils.getConn();
			String sql=" select id,username,pwd,email,admin from user where id=? ";
			pstm=conn.prepareStatement(sql);
			pstm.setInt(1, id);
			rs=pstm.executeQuery();
			while(rs.next()) {
				u=new User(rs.getInt("id"),rs.getString("username"),rs.getString("pwd"),rs.getString("email"),rs.getString("admin")); 
			}
			return u;
		} catch (SQLException e) {
			System.out.println("查询失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(rs, pstm, conn);
		}
		return null;
	}

	@Override
	public List queryAll() {
		Connection conn=null;
		PreparedStatement pstm=null;
		ResultSet rs=null;
		User u=null;
		List users=new ArrayList<>();
		try {
			conn=DBUtils.getConn();
			String sql=" select id,username,pwd,email,admin from user ";
			pstm=conn.prepareStatement(sql);
			rs=pstm.executeQuery();
			while(rs.next()) {
				u=new User(rs.getInt("id"),rs.getString("username"),rs.getString("pwd"),rs.getString("email"),rs.getString("admin"));
				users.add(u);
			}
			return users;
		} catch (SQLException e) {
			System.out.println("查询失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(rs, pstm, conn);
		}
		return null;
	}

	@Override
	public List queryByName(String name) {
		Connection conn=null;
		PreparedStatement pstm=null;
		ResultSet rs=null;
		User u=null;
		List users=new ArrayList<>();
		try {
			conn=DBUtils.getConn();
			String sql=" select id,username,pwd,email,admin from user where username like ? ";
			pstm=conn.prepareStatement(sql);
			pstm.setString(1, "%"+name+"%");
			rs=pstm.executeQuery();
			while(rs.next()) {
				u=new User(rs.getInt("id"),rs.getString("username"),rs.getString("pwd"),rs.getString("email"),rs.getString("admin"));
				users.add(u);
			}
			return users;
		} catch (SQLException e) {
			System.out.println("查询失败");
			e.printStackTrace();
		}finally {
			DBUtils.close(rs, pstm, conn);
		}
		return null;
	}

}

controller层，即业务逻辑层

写了UserService接口，用UserServiceImpl实现，此处UserService略去不写

package com.cyz.service;

import java.util.List;

import com.cyz.dao.User;
import com.cyz.dao.UserDao;
import com.cyz.dao.UserDaoImpl;
import com.cyz.view.AdminView;
import com.cyz.view.UserView;

public class UserServiceImpl implements UserService {

	@Override
	public boolean register(User u) {

		UserDao ud = new UserDaoImpl();
		if (!u.getUsername().equals("")&&!u.getPwd().equals("")&&ud.queryByUsername(u.getUsername()) == null && ud.addUser(u)) {
			return true;
		}
		return false;
	}

	@Override
	public boolean login(String username, String pwd) {
		UserDao ud = new UserDaoImpl();
		User u = null;
		if ((u = ud.queryByNameAndPwd(username, pwd)) != null) {
			System.out.println("登录成功");
			if (u.getAdmin().equals("管理员")) {
				AdminView.show(u);
			} else {
				UserView.show(u);
			}
			return true;
		}
		System.out.println("登录失败，用户名或密码错误");
		return false;
	}

	@Override
	public User userInfo(String username) {
		UserDao ud = new UserDaoImpl();
		User u = ud.queryByUsername(username);
		return u;
	}

	@Override
	public boolean userModify(User u) {
		UserDao ud = new UserDaoImpl();
		if (ud.queryByUsername(u.getUsername()) == null && ud.modifyUser(u)) {
			System.out.println("修改成功");
			return true;
		}
		System.out.println("用户名已存在，修改失败");
		return false;
	}

	@Override
	public boolean delUser(int id) {

		UserDao ud = new UserDaoImpl();
		if (ud.queryById(id) != null && ud.delUser(id)) {
			System.out.println("删除成功");
			return true;
		}
		System.out.println("用户不存在");
		return false;
	}

	@Override
	public boolean adminModifyUser(User u) {
		UserDao ud = new UserDaoImpl();
		if (ud.queryById(u.getId()) != null) {
			if (ud.queryByUsername(u.getUsername()) == null && ud.modifyUser(u)) {
				System.out.println("修改成功");
				return true;
			} else {
				System.out.println("用户名已存在，修改失败");
			}
		} else {
			System.out.println("该id不存在，修改失败");
		}
		return false;

	}

	@Override
	public List queryAll() {
		UserDao ud = new UserDaoImpl();
		List users = ud.queryAll();
		return users;
	}

	@Override
	public User queryById(int id) {
		UserDao ud = new UserDaoImpl();
		User u = ud.queryById(id);
		return u;
	}

	@Override
	public List queryByName(String name) {
		
		UserDao ud=new UserDaoImpl();
		List users=ud.queryByName(name);
		return users;
	}

}

主函数调用主界面run()方法，直接运行

package com.cyz.main;

import com.cyz.view.MainView;

public class MainApp {

	public static void main(String[] args) {
		MainView.run();
		return;
	}
}