jdbc篇第4课：封装Dbc

  这节课开始我们开始讲封装jdbc

 

  分析:

在前面几课中，我们都要先建立连接，获取Connection对象，而且代码是重复的，我们可以将这部分代码提取出来

 

  实现:

package com.tool;



import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;



//Database Connection，负责连接数据库，返回一个Connection对象

public class Dbc {



    //不允许调用构造器

    private Dbc(){}



    public static Connection getConnection(String driver,String url,String user, String password) throws ClassNotFoundException, SQLException {

        Class.forName(driver);

        return DriverManager.getConnection(url,user,password);

    }

}

 

  测试代码:

public static void main(String[] args) throws SQLException, ClassNotFoundException {

    String driver = "com.mysql.jdbc.Driver";

    String url = "jdbc:mysql://localhost:3306/teach";

    String user = "root";

    String password = "root";

    Connection conn = Dbc.getConnection(driver, url, user, password);



    //测试下连接是否真的可用

    Statement statement = conn.createStatement();

    String sql = "select * from tbl_employee where id = 1";

    ResultSet resultSet = statement.executeQuery(sql);

    resultSet.next();

    System.out.println(resultSet.getInt(1));

    System.out.println(resultSet.getString(2));

    //连接确实可用

}

 

  结果:

1

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