public class JDBCUtil {
private static String driver;
private static String url;
private static String username;
private static String password;

/**
 * 静态代码块加载配置文件信息
 */
static {
    try {
        // 1.通过当前类获取类加载器
        ClassLoader classLoader = JDBCUtil.class.getClassLoader();
        // 2.通过类加载器的方法获得一个输入流
        InputStream is = classLoader.getResourceAsStream("db.properties");
        // 3.创建一个properties对象
        Properties props = new Properties();
        // 4.加载输入流
        props.load(is);
        // 5.获取相关参数的值
        driver = props.getProperty("driver");
        url = props.getProperty("url");
        username = props.getProperty("username");
        password = props.getProperty("password");
    } catch (IOException e) {
        e.printStackTrace();
    }
}

/**
 * 获取连接方法
 * 
 * @return
 */
public static Connection getConnection() {
    Connection conn = null;
    try {
        Class.forName(driver);
        conn = DriverManager.getConnection(url, username, password);
    } catch (Exception e) {
        e.printStackTrace();
    }
    return conn;
}
/**
 * 释放资源方法
 * 
 * @param conn
 * @param pstmt
 * @param rs
 */
public static void release(Connection conn, PreparedStatement pstmt, ResultSet rs) {
    if (rs != null) {
        try {
            rs.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    if (pstmt != null) {
        try {
            pstmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    if (conn != null) {
        try {
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

}

}