Java Applet & SQL JDBC Driver

gogul

Hi,

I'm tryin to create an applet that will display live updates in a sql table. I have the code working in a command prompt environment, but once I try to insert the code into an applet, I get a SQL error. I think it's something to do with the driver; the only error I get I display in the Applet and it's as follows:
"com.microsoft.sqlserver.jdbc.SQLServerDriver".

That's it!

Any ideas?

gogul

Seth Brundle

show us the code.
have a look at this - it may help...
http://adams.patriot.net/~tvalesky/jdbc.html

gogul

Hmm, that code looks good, but I want to stay away from using a JDBC-ODBC bridge. I'm just looking for a direct applet connection using JDBC only.

The connect code is below. This works at a normal console level, but seems to have problems with applets. I have checked on this and it seems that the the error I'm having may be linked to the applet being unable to locate the driver. Only problem is, that I dont know how to successgfully link the driver with the applet.

Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection con = DriverManager.getConnection("jdbc:sqlserver://127.0.0.1;databaseName=TestDB;user=user;password=password");

Seth Brundle

what about the DB port?
DriverManager.getConnection("jdbc:microsoft:sqlserver://127.0.0.1:1433;user=user;password=password")

Also read this - http://support.microsoft.com/default.aspx?scid=kb;en-us;839569

gogul

kbannon wrote:

what about the DB port?
DriverManager.getConnection("jdbc:microsoft:sqlserver://127.0.0.1:1433;user=user;password=password")

Also read this - http://support.microsoft.com/default.aspx?scid=kb;en-us;839569

No, I've also tried the port and it doesnt work. It's a definite driver issue

Seth Brundle

have you got the correct driver?
http://www.microsoft.com/downloads/details.aspx?FamilyID=9f1874b6-f8e1-4bd6-947c-0fc5bf05bf71&DisplayLang=en

See this also...
http://forum.java.sun.com/thread.jspa?threadID=691397

pH

quick thoughts -

Is the sqlserver.jar in the correct place on the web-server, and specified properly in the <APPLET> tag ? - check this by writing a bit of test code that referes to a class in the jar explicitly and check for a noclassdef exception.

an applet can only connect back to the machine it came from (I believe that DNS and what the machine is called is important) Is the sqlserver on the same machine as the webserver and do you refer to them using the exact same url?

gogul

pH wrote:

quick thoughts -

Is the sqlserver.jar in the correct place on the web-server, and specified properly in the <APPLET> tag ? - check this by writing a bit of test code that referes to a class in the jar explicitly and check for a noclassdef exception.

an applet can only connect back to the machine it came from (I believe that DNS and what the machine is called is important) Is the sqlserver on the same machine as the webserver and do you refer to them using the exact same url?

I'm just running the applet using appletviewer in command prompt. It will never be on a website except to run locally on a machine through IE. I'm not sure how to set the <APPLET> tage properties on this? Can you help?

Seth Brundle

http://www.w3schools.com/tags/tag_applet.asp
http://www.htmlcodetutorial.com/applets/_APPLET.html
http://www.aprs-is.net/javAPRS/applet.htm

gogul

So, do I have to reference the jdk directory with the codebase tag?

pH

Are you sure you should be using an applet then?

Depending on how you do this - if it's production code then your classes should be in a jar (signed) and that jar's manifest should specify the jars it depends on.

However this may work:

<applet
CODEBASE="/where to find jars"
code=Applet.class
archive="YOUR.jar, mssqlserver.jar"
width=800 height=400>
</applet>

or something similar

Seriously why not just change it from an applet to a JFrame and run it from the PC?

Just add a static main method

public class MyApplet extends JApplet {

  ...

  public static void main(String[] args) {

    Component applet = new MyApplet();

    JFrame frame = new JFrame("My applet, as application");
    frame.getContentPane().add(applet);

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.show();
}

http://www.devx.com/tips/Tip/16650

gogul

pH wrote:

Are you sure you should be using an applet then?....

Yeah I have been thinking that alright. It was just that I am more familiar with using Applets (except when it comes to DB connections, lol). I have tried the code in a JFrame and it connects fine.

I guess a JFrame is the best option so, but that Aplpet issue is really bugging me now. Anyway, thanks for your help on this lads.

gogul