请尝试此代码：

<table width="59%" border="1">
    <%
        MySql1 o = new MySql1();
        o.connect();
        ResultSet r;
        int counter=1;
        String q = "select * from category_master;";
        r = o.getdata(q);
        ResultSetMetaData metaData = r.getMetaData();
        while(r.next())
        {
            %>
                <tr>
                 <%
                 for(int i = 1; i<=metaData.getColumnCount();i++)
                    { %>
                     <td>
                     <%= r.getString(i)%>
                     </td>
                <% 
                    }
                %>                   
                </tr>
            <% 
        }
    %>
</table>