我得到了上面的错误和下面是我的代码我做错了什么？错误引用到数据源.什么是问题？

public class DBConnector {
private Connection dbConn = null;
private FileLogger fileLogger = new FileLogger("./logs/logfile.txt");
private ConfigurationReader conf = new ConfigurationReader("./config.sys");
private Logger logger = fileLogger.getLogger();

/**
 * Attempts to establish a connection with a test MySQL database.
 */
public DBConnector() {

    MysqlDataSource dataSource = new MysqlDataSource();
    dataSource.setUser(conf.getConfigString("username"));
    dataSource.setPassword(conf.getConfigString("password"));
    dataSource.setServerName(conf.getConfigString("dbhost"));
    dataSource.setDatabaseName(conf.getConfigString("dbname"));
    dataSource.setPort(conf.getConfigInt("dbport"));

    try {
        dbConn = dataSource.getConnection();

        logger.info("Succesful connection with database!");
    } catch (Exception ex) {
        logger.info("Error: DBConnector(): problem creating database connection");
    }
    logger.info("Database connection = " + dbConn);
}