如何在整个类中使用配置属性文件？

database.url=jdbc:mysql://localhost:3306/mydatabase
database.username=root
database.password=password

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

public class MyClass {
    private Properties properties;

    public MyClass() {
        properties = new Properties();
        InputStream inputStream = getClass().getResourceAsStream("/config.properties");
        try {
            properties.load(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public void connectToDatabase() {
    String url = properties.getProperty("database.url");
    String username = properties.getProperty("database.username");
    String password = properties.getProperty("database.password");

    // 使用上述属性连接到数据库
}