package jess.day15;

import java.io.FileInputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
/**
 * @author Jess
 * @date 2021/10/19
 */
public class Conn {
    public static void main(String[] args) throws SQLException, IOException, ClassNotFoundException {
        conn2();
    }

    /**
     * 直接读取字符串
     */
    public static void  conn1() {
        String url = "jdbc:mysql://127.0.0.1:3306/jzy1?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8";
        String name = "root";
        String password = "123456";
        String driver = "com.mysql.cj.jdbc.Driver";
        try {
            Class.forName(driver);
            Connection connection = DriverManager.getConnection(url, name, password);
            System.out.println(connection);
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * 通过配置文件读取
     */
    public static void conn2() throws IOException, ClassNotFoundException, SQLException {
        Properties properties =new Properties();
        // 读取配置文件
        properties.load(new FileInputStream("jdbc.properties"));
        // 解析配置文件
        String url = properties.getProperty("url");
        String name = properties.getProperty("name");
        String password = properties.getProperty("password");
        String driver = properties.getProperty("driver");
        System.out.println(url);
        // 加载驱动
        Class.forName(driver);
        // 获取连接
        Connection connection = DriverManager.getConnection(url, name, password);
        System.out.println(connection);
    }
}

properties配置文件
url =jdbc:mysql://127.0.0.1/jzy2?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
name =root
password =123456
driver =com.mysql.cj.jdbc.Driver

 连接数据库的工具类

package cn.jess.day02;

import cn.jess.day01.JdbcTest;
import java.io.IOException;
import java.sql.*;
import java.util.Properties;

/**
 * 连接数据库
 * @author Jess
 */

public class JdbcConnectionTool {
    /**
     * 获取连接
     * @return 连接对象
     */
    public static Connection getConnection() {
        Properties properties = new Properties();
        Connection con = null;
        try {
            //加载配置文件
            properties.load(JdbcTest.class.getClassLoader().getResourceAsStream("jdbc.properties"));
            // 读取配置文件
            String url = properties.getProperty("mysql.url");
            String user = properties.getProperty("mysql.username");
            String password = properties.getProperty("mysql.password");
            //获取连接
            con = DriverManager.getConnection(url, user, password);
        } catch (IOException | SQLException e) {
            e.printStackTrace();
        }
        return con;
    }

    /**
     * 关闭资源
     * @param statement
     * @param connection
     * @param resultSet
     */
    public  static void connClose(Statement statement,Connection connection,ResultSet resultSet){
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
}