面向对象的jdbc

偏执的太偏执、 2022-03-19 13:51 71阅读 0赞

package test;
    
    import java.util.Scanner;
    
    import entity.User;
    import service.UserSerivce;
    import service.impl.UserServiceImpl;
    
    public class Client {
    	public static void main(String[] args) {
    		Scanner sc = new Scanner(System.in);
    		System.out.println("请输入用户名：");
    		String username = sc.next();
    		System.out.println("请输入用户名：");
    		String password = sc.next();
    		User user = new User();
    		user.setPassword(password);
    		user.setUsername(username);
    		UserSerivce userSerivce = new UserServiceImpl();
    		User u = userSerivce.login(user);
    		if(u== null) {
    			System.out.println("用户名密码错误..");
    		}else {
    			System.out.println(u.getId()+"\t"+u.getUsername()+"\t"+u.getPassword());
    		}
    		
    	}
    }
    
    package dao;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    public abstract class DataBase {
    	public static Connection conn = null;
    	public static PreparedStatement pstm = null;
    	public static ResultSet rs = null;
    	/**
    	 * 得到数据连接
    	 */
    	public static Connection getConn() {
    		try {
    			String url = "jdbc:oracle:thin:@localhost:1521:orcl";//易错点
    			String username = "scott";
    			String password = "tiger";
    			Class.forName("oracle.jdbc.driver.OracleDriver");//易错点
    			conn = DriverManager.getConnection(url, username, password);
    		} catch (ClassNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		return conn;
    	}
    
    	/**
    	 * 关闭连接
    	 */
    	public static void close() {
    		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();
    		}
    
    	}
    }
    
    package dao.impl;
    
    import java.sql.SQLException;
    
    import dao.DataBase;
    import dao.UserDao;
    import entity.User;
    
    public class UserDaoImpl implements UserDao {
    
    	@Override
    	public User getUser(User user) {
    		// TODO Auto-generated method stub
    		String sql = "select userid,username,password from "
    				+ "t_user where userid=? and username = ? and password = ?";
    				  //易错点，有三个user对象就必须有三个？
    		User u = null;
    		try {
    			DataBase.conn = DataBase.getConn();
    			DataBase.pstm = DataBase.conn.prepareStatement(sql);
    			DataBase.pstm.setInt(1, 1);//这里setInt（，）；第一个是rs索引，一个是use的对象值
    			DataBase.pstm.setString(2, user.getUsername());
    			DataBase.pstm.setString(3, user.getPassword());
    			DataBase.rs = DataBase.pstm.executeQuery();
    			while(DataBase.rs.next()) {
    				u = new User();
    				u.setId(DataBase.rs.getInt("userid"));
    				u.setUsername(DataBase.rs.getString("username"));
    				u.setPassword(DataBase.rs.getString("password"));
    			}
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		return u;
    	}
    
    }
    
    package service.impl;
    
    import dao.UserDao;
    import dao.impl.UserDaoImpl;
    import entity.User;
    import service.UserSerivce;
    
    public class UserServiceImpl implements UserSerivce {
    	UserDao userDao = new UserDaoImpl();
    
    	@Override
    	public User login(User user) {
    		// TODO Auto-generated method stub
    		return userDao.getUser(user);
    	}
    
    }
    
    package entity;
    
    public class User {
    	private int id;
    	private String username;
    	private String password;
    
    	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;
    	}
    }
    
    package service;
    
    import entity.User;
    
    public interface UserSerivce {
    	public User login(User user);
    }
    
    package dao;
    
    import entity.User;
    
    public interface UserDao {
    	public User getUser(User user);
    }