properties配置文件内容如下：

driverName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/db_accountSystem
user=root
password=admin

Java代码如下：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

public class Test {
    public static void main(String[] args) throws IOException {
        // 实例化Properties对象
        Properties properties = new Properties();
        // 加载properties配置文件
        properties.load(new FileInputStream(new File("src\\AccountSystem\\dao\\db.properties")));
        // 通过键名获取对应的值
        String driverName = properties.get("driverName").toString();
        String url = properties.get("url").toString();
        String user = properties.get("user").toString();
        String password = properties.get("password").toString();
        // 控制台打印
        System.out.println("driverName: " + driverName + "\nurl: " + url + "\nuser: " + user + "\npassword: " + password);
    }
}

控制台打印：