private ConnectionUtil(){
		
		if( dbType.equals("mysql")){
			try {
				Class.forName("com.mysql.jdbc.Driver");
				conn = DriverManager.getConnection(urlMysql);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}else if( dbType.equals("oracle")){
			try {
				Class.forName("oracle.jdbc.driver.OracleDriver");
				conn = DriverManager.getConnection(urlOracle, "tankwar", "tankwar");
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}