Java file reading and Stroing in array

[Basher]

OK, I currently have the follwoing:

The code should read from the file stock.txt and put the info into the array in the prog (arrays already declared etc) however i just get nullpointer errors and non displaying of the data in the file.

Could anyone offer any help i.e. have I made any really obvious mistakes?


File stockFile = new File("stock.txt");

if (!stockFile.exists())
{
return;
}

BufferedReader input=
new BufferedReader(
new FileReader(stockFile));

int count=1;

stockCode[count] = input.readLine();
stockDesc[count] = input.readLine();
String strCurrentLevel = input.readLine();
currentLevel[count] = Integer.parseInt(strCurrentLevel);
String strReorderLevel = input.readLine();
reorderLevel[count] = Integer.parseInt(strReorderLevel);
String strPrice = input.readLine();
price[count] = Float.parseFloat(strPrice);

while (stockCode!=null)
{
System.out.print("\t"+stockCode[count]);
System.out.print("\t\t"+stockDesc[count]);
System.out.print("\t\t"+currentLevel[count]);
System.out.print("\t\t"+reorderLevel[count]);
System.out.print("\t\t"+price[count]);
count++;
stockCode[count] = input.readLine();
stockDesc[count] = input.readLine();
strCurrentLevel = input.readLine();
currentLevel[count] = Integer.parseInt(strCurrentLevel);
strReorderLevel = input.readLine();
reorderLevel[count] = Integer.parseInt(strReorderLevel);
strPrice = input.readLine();
price[count] = Float.parseFloat(strPrice);


}
input.close();

Thanks in advance

[DaBeeeenster]

Can you post the textfile as well?

[DaBeeeenster]

Just looking at some code for one of our products, this is how we do it:

FileInputStream fis = new FileInputStream("file.txt");
BufferedReader myInput = new BufferedReader(new InputStreamReader(fis));
String thisLine = "";

while ((thisLine = myInput.readLine()) != null) {
    System.out.println(thisLine);
}

[Basher]

Stock Code
Stock Description
500
540
29

That's what's in the text file, I'll give your suggestion above a go and I'll let you know how I get on.

Thanks muchly

[Basher]

Just looking at some code for one of our products, this is how we do it:

FileInputStream fis = new FileInputStream("file.txt");
BufferedReader myInput = new BufferedReader(new InputStreamReader(fis));
String thisLine = "";

while ((thisLine = myInput.readLine()) != null) {
    System.out.println(thisLine);
}

hmm yeah that works for one variable, but I need to cycle through all of my variables putting them into their array each time, how would i modify this code to do that?

[DsW]

Hi,

Firstly, what code are you using to initialise the array?

Secondly, remember that array indexes start at 0 (not 1).

Thirdly, the expression

while (stockCode!=null)

will always be true if you have initialised the array properly and this loop will just run and run.

Not sure exactly what you are trying to achieve here, but if its just read the contents of a file, store the values and print them out then I would read the entire file in first then iterate over your data structure and print things out seperately - keep it simple.

Reading the contents of a file should be done using something like

while ((c = in.read()) != -1)

This will terminate the loop once it encounters end of file.

Array iteration is best done using an expression such as

for (int i=0; i<array.length; i++)

Best practice code for file I/O this can be found here -
http://java.sun.com/docs/books/tutor...lestreams.html

hope this helps,
dave

[Basher]

while ((c = in.read()) != -1)

Yeah I tried that , but only got it to work with one variable, I need to store all of my variables into their arrays how would I go about this, could i just simply use && in the above line specifiing each new line from teh file to go to the relevant array space?

Thanks for your help

[killgORE]

k.. do you want a solution ? Assuming that you want it implemented the same way you tried it. Without my petty wanting each record to be an object, and simply having an array of these objects. This is how you would do it...

This reads in a text file filling the arrays. You call the program like this...
java HexusProb <filename>. If you do not specify a file. it will crash.
Then it prints out the arrays to the terminal console.
--------------------------------------------------------------------
import java.io.* ;

public class HexusProb {
/*Declare arrays, ten is arbitrary value */
static String[] StockCode = new String[10] ;
static String[] StockDesc = new String[10] ;
static int[] CurrentLevel = new int[10] ;
static int[] ReorderLevel = new int[10] ;
static float[] Price = new float[10] ;

public static void main(String[] args) {

try {

BufferedReader fileIn =
new BufferedReader(new FileReader(args[0]));

int count = 0 ;

String in = fileIn.readLine() ;
while(in!=null) {

StockCode[count] = in ;
StockDesc[count] = fileIn.readLine() ;
CurrentLevel[count] = Integer.parseInt(fileIn.readLine()) ;
ReorderLevel[count] = Integer.parseInt(fileIn.readLine()) ;
Price[count] = Float.parseFloat(fileIn.readLine()) ;
in = fileIn.readLine() ;
count++ ; /* increment counter */
} /* End of while */

} catch(IOException ioe) {
ioe.printStackTrace() ;
}

displayRecords() ;
System.exit(0) ;

} /* End of main */

/* This prints out the arrays to the console */
public static void displayRecords() {

for (int i = 0 ; i <= (StockCode.length-1) ; i++) {

if(StockCode[i]==null)
return ; /* end of useful data */

System.out.print("\t"+StockCode[i]);
System.out.print("\t\t"+StockDesc[i]);
System.out.print("\t\t"+CurrentLevel[i]);
System.out.print("\t\t"+ReorderLevel[i]);
System.out.print("\t\t"+Price[i]);

}

}
}

----------------------------------------------
I may have got a little excited by the fact there was finally a Java problem !

[Basher]

thanks muchly for your help

[Basher]

hmm just tried that, it reads the first line fine but not the second, third etc etc.

here's the two necessary files, it compiles fine just has trouble when in the prog itself, i.e. it can't do certain things like find the second item succesfully or extend/increase stock.

Take a looksy at these ....

http://www.jmbradley.net/StockControl.java
http://www.jmbradley.net/stock.txt

[Basher]

Ahh finally all sorted

[killgORE]

What was the prob mate ? It worked fine for me ! using a textfile of the data you posted earlier.

Glad to hear its sorted though.

[Basher]

it was a combination of things really, a bit of tidying up later and it works fine

Thanks for all your help

[killgORE]

Incidently. I have been looking for some posts to let me help with java problems. This helps me... as I have to think a bit while I fix problems, and helps the poster. So if there are anymore problems then just make a post in this programming section. Not that I am some sort of uber Java guru. But I am trying real hard to be !

[DsW]

Incidently. I have been looking for some posts to let me help with java problems. This helps me... as I have to think a bit while I fix problems, and helps the poster. So if there are anymore problems then just make a post in this programming section. Not that I am some sort of uber Java guru. But I am trying real hard to be !

I think the best approach for helping people to learn is to point them in the right direction rather than giving them a complete solution.

This way people have to actually think about what they are doing wrong and work towards finding and understanding the right way to do it.

cheers,
dave

[killgORE]

Hmmmm. I take this onboard, and this is the way I teach people when I am sitting in the same room as them. I figure out what is wrong... then ask them little questions till they find the problem themself - as this is best. But this is a little time consuming through a web forum don't you think ? Suppose there is always good old ICQ...