public static JTable getJTable(){   //JTable

        sql="SELECT * FROM Pwd";        //sql䣬ñ

        Vector data = new Vector();     //
        Vector dataRow = new Vector();  //ÿе

        ResultSet rs=DB.sqlQuery(sql);      //òѯ

        int colNum=4;               //

        try {
            while (rs.next()) {
                //µһм¼
                dataRow = new Vector ();
                for (int i = 1; i <= colNum; i ++) {
                    dataRow.add(rs.getString(i).toString());
                }

                //ӵܽ
                data.add(dataRow);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }

        Vector cols = new Vector();     //
        cols.addElement("");
        cols.addElement("");
        cols.addElement("");
        cols.addElement("ע");
        tableModel = new DefaultTableModel(data, cols);     //񣬲
        table = new JTable(tableModel);

        return table;       //ر
    }