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placing values in an array

Posted on 2003-11-05
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Last Modified: 2010-04-01
i have an array ar[] and i want to store values in it from the databse,how will i do it?
this is just a part of the code:
 
String[] arr = null;
i nt i = 0 ;
while(rs2.next()){
String duid = rs2.getString("userid");
String ddn = rs2.getString("dn");
String dtn = rs2.getString("tn");                        
arr[i] = dtn;
i++;
}statement2.close();connection2.close();%>

i want to put the values dtn in my array arr[] and pass it to a bean.
hop u can help me on this.thanks.
0
Comment
Question by:kurisuchine22
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8 Comments
 
LVL 15

Expert Comment

by:jimmack
ID: 9692927
The problem is that you don't know how big the ResultSet is until you've iterated through it.

It is easier to store the data in an ArrayList so that it can "grow" as you add new elements, then convert that to an array later (or better yet, just store the ArrayList in your bean).

ArrayList arr = new ArrayList();

while...
.
.
String dtn = rs2.getString("tn");
arr.add(dtn);

You don't need the "i" counter then either.
0
 
LVL 1

Accepted Solution

by:
JNic earned 20 total points
ID: 9697178
I dont know the details of your application, but if it is a multi-thread-environment, I would use Vector instead of ArrayList, since it is synchronized. This is the main difference between the two classes.

Example with Vector:

import java.util.Vector;

Vector arr = new Vector();

while..
.
.
String dtn = rs2.getString("tn");
arr.addElement(dtn);

Regards,

Nic
0
 

Expert Comment

by:tizay
ID: 9698527
thanks nic
0
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LVL 15

Expert Comment

by:jimmack
ID: 9699829
I'm not happy about this.  JNic simply copied my answer with a different container.

I'll give it 24 hours before I contact CS to resolve this.
0
 
LVL 1

Expert Comment

by:JNic
ID: 9700177
Sorry jimmack, I did not mean to steal your points! :-(
I just thought a Vector would be more suitable in a threaded environment since it is synchronized, and to make it simple, I used your example again, since tizay obviously is not yet a wizard in java.

Would it satisfy you, if I posted 20 points for you, or how would you like it?

Regards,

Nic
0
 
LVL 15

Expert Comment

by:jimmack
ID: 9700237
Hi JNic.

If you don't mind, that would be good :-)

My comment was really for kurisuchine22.  I know you can't split 20 points, but the fact that their comment showed no recognition for my contribution really annoyed me.

Thanks JNic ;-)

(BTW: I'd use add() instead of addElement().  addElement() is not deprecated (yet), but if you use add(), you can switch between other containers - like ArrayList - without changing the methods ;-))
0
 
LVL 1

Expert Comment

by:JNic
ID: 9700290
Ooooooooops - SORRY TIZAY!
I meant of course kurisuchine22 (blush)

Thanks for you comment updon addElement jimmack. I'll post some points for you ! :-)
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Expert Comment

by:tizay
ID: 9712311
how come you guys are fighting over my question?i dont want to cause arguments in this page.hope you understand.i'm just asking a question.:-)
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