java 读取properties文件

driver=com.mysql.jdbc.Driver
url=jdbc\:mysql\://localhost\:3306/qqonline
user=root
password=

public class DBUtil {
 　　private static String driver = "";
    private static String url = "";
    private static String user = "";
    private static String password = "";
    private static boolean flag = false;
    /**
     * 加载JDBC连接数据库参数
     */
    public void getParm(){
        Properties p = new Properties();
        try {
            InputStream in =  this.getClass().getClassLoader().getResourceAsStream("config.properties");            
            p.load(in);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        driver = p.getProperty("driver");
        url = p.getProperty("url");
        user = p.getProperty("user");
        password = p.getProperty("password");
        flag = true;
    }
　　public static Connection getConnection(){
　　  if(!flag){//每次连接的时候都看下加载了没
    　DBUtil db = new DBUtil();
     db.getParm();
　　}

}