小朋友你是否有很多问号？？？？？？？？？？？？

 1、在资源文件中建一个文件，填入连接数据库的基本信息。

 2、通过反射拿到资源文件。

你说你不只知道什么是反射？？？？？ （那你可得认真看这篇博客了）

你还不会反射吧，快来吧！！！_明天更新的博客-CSDN博客

  Class<Doem> doemClass = Doem.class;
            InputStream is = doemClass.getClassLoader().getResourceAsStream("DomeJdbc");

        2. 取出资源文件中的连接信息。。。

        Class<Doem> doemClass = Doem.class;
        InputStream is = doemClass.getClassLoader().getResourceAsStream("DomeJdbc");
        //InputStream is=Thread.currentThread().getContextClassLoader().getResourceAsStream("DomeJdbc");
        Properties prop = new Properties();
        try {
            prop.load(is);
            String driver = prop.getProperty("db.driver");
            String url = prop.getProperty("db.url");
            String username = prop.getProperty("db.username");
            String password = prop.getProperty("db.password");
        } catch (Exception e) {
        }
    }


}

3.连接数据库，编写代码。

/*
 * Copyright (c) 2020, 2023,  All rights reserved.
 *
 */
package cn.scl;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

/**
 * <p>Project: jdbcfirst - Doem</p>
 * <p>Powered by scl On 2023-08-11 13:55:30</p>
 * <p>描述：<p>
 *
 * @author scl [1846080280@qq.com]
 * @version 1.0
 * @since 17
 */
public class Doem {
    @Test
    void show1() {
        Class<Doem> doemClass = Doem.class;
        InputStream is = doemClass.getClassLoader().getResourceAsStream("DomeJdbc");
        //InputStream is=Thread.currentThread().getContextClassLoader().getResourceAsStream("DomeJdbc");
        Properties prop = new Properties();
        try {
            prop.load(is);
            String driver = prop.getProperty("db.driver");
            String url = prop.getProperty("db.url");
            String username = prop.getProperty("db.username");
            String password = prop.getProperty("db.password");
            //Class.forName(driver);
            Connection con = DriverManager.getConnection(url, username, password);
            System.out.println(con);
            Statement st = con.createStatement();
            for (int i = 0; i < 10; i++) {
                st.execute(String.format("create database if not exists user%d",i));
            }
        } catch (Exception e) {
        }
    }

}

看结果：