第一種： 通過ResourceBundle獲取
ResourceBundle bunble = ResourceBundle.getBundle("db");
driver = bunble.getString("driver");
url = bunble.getString("url");
username = bunble.getString("username");
password = bunble.getString("password");

第二種：通過類加載器獲取
// 1. 通過當前類獲取類加載器   訪問方式： 類型.class.getClassLoader()
ClassLoader classLoader = JDBCUtils_V3.class.getClassLoader();
// 2. 通過類類加載器獲取一個輸入流
InputStream is = classLoader.getResourceAsStream("db.properties");
// 3. 創建properties對象
Properties p = new Properties();
// 4. 加載輸入流
p.load(is);
// 5. 獲取相關參數的值
driver = p.getProperty("driver");
url = p.getProperty("url");
username = p.getProperty("username");
password = p.getProperty("password");
 

java讀取properties文件