配置文件的读取

（1）配置文件放在项目的根目录下

Properties properties = new Properties();
InputStream is = new FileInputStream("config.properties");

// 导入输入流
properties.load(is);

// 读取
driverClass = properties.getProperty("driverClass");
url = properties.getProperty("url");
username = properties.getProperty("username");
password = properties.getProperty("password");

（2）配置文件放在src目录下

Properties properties = new Properties();
InputStream is = JDBCutils.class.getClassLoader().getResourceAsStream("config.properties");

// 导入输入流
properties.load(is);

// 读取
driverClass = properties.getProperty("driverClass");
url = properties.getProperty("url");
username = properties.getProperty("username");
password = properties.getProperty("password");