java连接数据库跪求高手,该如何处理

public class ConnDB {    public Connection conn = null;     public Statement stmt = null;     public ResultSet rs = null;     private static String propFileName = "/connDB.properties"; // 指定资源文件保存的位置    private static Properties prop = new Properties(); // 创建并实例化Properties对象的实例    private static String dbClassName = "";//定义保存数据库驱动的变量    private static String dbUrl = "";    private static String dbUser = "";    private static String dbPwd = "";        //定义构造方法    public ConnDB() {            try {                        //将Properties文件读取到InputStream对象中            InputStream in = getClass().getResourceAsStream(propFileName);            prop.load(in); // 通过输入流对象加载Properties文件            dbClassName = prop.getProperty("DB_CLASS_NAME",dbClassName); // 获取数据库驱动            dbUrl = prop.getProperty("DB_URL", dbUrl);        //获取URL            dbUser = prop.getProperty("DB_USER", dbUser);    //获取登录用户            dbPwd = prop.getProperty("DB_PWD", dbPwd);        //获取密码                    } catch (Exception e) {            e.printStackTrace();         }    }    public Connection getConnection() {        System.out.println("前conn="+conn);        try {            System.out.println("1111111");            Class.forName(dbClassName);            conn = DriverManager.getConnection(dbUrl, dbUser, dbPwd);            System.out.println("数据库连接成功！"+dbUrl);                    } catch (Exception ee) {            ee.printStackTrace();        }        System.out.println("后conn="+conn);        if (conn == null) {            System.err.println("警告: DbConnectionManager.getConnection() 获得数据库链接失败.\r\n\r\n链接类型:"                            + dbClassName                            + "\r\n链接位置:"                            + dbUrl                            + "\r\n用户"                            + dbUser + "\r\n密码"+ dbPwd);        }        return conn;    }