Re: converting some VB code to Java..

"Bjorn Abelli" <>
30 May 2006 10:18:58 +0200
"maya" <> wrote...

Bjorn Abelli wrote:

A simple Google gives plenty of sites with AJAX connected to Java:

Why not from the horses mouth, Sun:

Plenty of examples there... ;-)

thank you Bjorn, I HAD searched in Google, and had found some stuff (among
others sun-pg you mention above) but can't find a step-by-step java-based
tutorial like the one here..

since you seem to know about AJAX I was wondering,

Actually, I had only heard of it, but never used it, before you asked for
it... ;-)

am looking for AJAX 'docs'...

I don't think anyone "owns" the concept. That would be Adaptive Path who
coined the expression:

closest thing I found is here...

why does XMLHTTPRequest have an "I" at the beginning here? (it's referred
to as "IXMLHTTPRequest")

Microsoft has a naming standard where interfaces "always" starts with an

That IXMLHTTPRequest is not "exactly" the same as XMLHTTPRequest, but as it
started in IE, MSDN is one source:

Other pages that explain the concepts are:

I would like to know what all the objs are that these properties & methods
can be applied to (is XMLHttpRequest the only obj here? or are there
others? I just need to get the "big picture" here....:)

So I'd suggest you get your hands dirty with JDBC, ResultSets,
PreparedStatements, etc... ;-)

I do know how to do db-stuff w/Java, Bjorn (probably not as much as you
do, but I do know how to connect to db, insert stuff into tables, do
updates and queries, etc..) right now I just need to figure out how to do
this in java:

  do until rs.EOF
    for each x in rs.Fields
      response.write("<tr><td><b>" & & "</b></td>")
      response.write("<td>" & x.value & "</td></tr>")

rs.EOF?? (resultSet EndOfFile? what does this mean?)

Yes, ADO has a slightly different approach than JDBC... ;-)

Other than that, the code would look quite similar, e.g.:


  while ( ())
     for (int i = 0; i < columnCount; i++)
             "<tr><td><b>" +
              rsMetaData.getColumnName(i+1) +
             "<td>" +
             rs.getString (i+1) +

....should be corresponding to the code you extracted.

ok, no more on AJAX questions (unless it's an AJAX/Java-related
question....:), since this is not an AJAX group.. have more JS/AJAX code
questions (xmlHttp.readyState=="complete" -- what is "complete"..), I
guess I need to switch to JS ng (I guess no AJAX-ng yet..)

Yep, that's on the client side...

again, many thanks for yr help..

You're welcome.

// Bjorn A

The servlet, not tested though...

import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class AjaxDatabaseServlet extends HttpServlet
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
                      throws ServletException, IOException
        PrintWriter out = response.getWriter();

        String sql =

        // You might want to fix the path to the database

        String url =
            "jdbc:odbc:DRIVER={Microsoft Access Driver (*.mdb)};DBQ=" +

               new sun.jdbc.odbc.JdbcOdbcDriver());

            Connection conn = DriverManager.getConnection (url);
            Statement stmt = conn.createStatement ();
            ResultSet rs = stmt.executeQuery (sql);
            ResultSetMetaData rsMetaData = rs.getMetaData();

            int columnCount = rsMetaData.getColumnCount();


            while ( ())
                for (int i = 0; i < columnCount; i++)
                        "<tr><td><b>" +
                        rsMetaData.getColumnName(i+1) +
                        "<td>" +
                        rs.getString (i+1) +



            // cleanup...

        catch (SQLException ex)

/// Bjorn A

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