java 怎么调用 vf数据库文件

public class DBA {

private String user = "db2inst1"; // 用户名

private String pwd = "1";// 密码

private String url = "jdbc:db2:web";// 连接地址字符串

private String driver = "COM.ibm.db2.jdbc.app.DB2Driver";// 连接驱动架包

private Connection conn;// 连接

private Statement sta;// 会话

private ResultSet res;// 结果

public static DBA dba;

public DBA() {
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, user, pwd);
System.out.println("conn db2 success");
sta = conn.createStatement();
} catch (ClassNotFoundException e) {
System.out.println("「 错误: 缺少架包支持 」");
e.printStackTrace();
} catch (SQLException e) {
System.out.println("「 错误: 用户名密码登陆错误 」");
e.printStackTrace();
}

}

public ResultSet querry(String sql