配置檔案

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC
username=root
password=123456  //設定的密碼

工具類

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

public class JdbcUtils {
    private static String driver=null;
    private static String url=null;
    private static String username=null;
    private static String password=null;
    static{
        try{
            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties");//db.properties"為配置檔名
            Properties properties = new Properties();
            properties.load(in);
            driver=properties.getProperty("driver");
            url=properties.getProperty("url");
            username=properties.getProperty("username");
            password=properties.getProperty("password");
            //驅動載入
            Class.forName(driver);
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    // 獲取連線
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url, username, password);
    }

    //釋放資源
    public static void release(Connection conn, Statement st, ResultSet rs) throws SQLException {
        if(rs!=null){
            rs.close();
        }
        if(st!=null){
            st.close();
        }
        if(conn!=null){
            conn.close();
        }
    }
}