Solved

BufferedReader

Posted on 2003-10-23
9
365 Views
Last Modified: 2010-03-31
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("input.txt")));
             String line = "";
             emptyfile(line, br);
             if ((line = br.readLine()) == null)
             {
                System.out.println("NO RECORD EXISTS IN OUR SYSTEM");
                EXIT();
             }
             while((line = br.readLine()) != null)
             {
                 StringTokenizer st = new StringTokenizer(line, "," );
                 String getCusId = st.nextToken();
                 System.out.println(getCusId);
                 if (getCusId.equals(customerId))
                 {
                     test = true;
                 }


--------------------------------------------------------------------------------
if the text file is like
1212121212,brian,1212// if loop test anf fails
1111122222,chow,1122 //while loop begin
....
....
how can i make the while loop read from the beginning of the text file again thanks for help, i know that may be a very easy question..

0
Comment
Question by:redsar
  • 5
  • 4
9 Comments
 
LVL 86

Accepted Solution

by:
CEHJ earned 40 total points
ID: 9605807
Why test first? Just read the file

boolean noRecords = true;
while((line = br.readLine()) != null)
{
     noRecords = false;
     // read the file and get info
}
0
 

Author Comment

by:redsar
ID: 9605940
i have tried
like this:
             boolean norecord = true;
             while((line = br.readLine()) != null)
             {
                 norecord = false;
                 StringTokenizer st = new StringTokenizer(line, "," );
                 String getCusId = st.nextToken();
                 if (getCusId.equals(customerId))
                     test = true;

              }
             if (norecord)
                //error,
          }
when the text file is null, it come up with error like this,
Exception in thread "main" java.util.NoSuchElementException
it seems it still read the element in the text file , and come upp with error
when using Tokenizer, how come this is not working,
so can i use
 catch(NoSuchElementException e)
          {
             System.out.println("NO RECORD EXIST");
             System.exit()          }
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 9605966
>>when the text file is null, it come up with error like this,

It can't be 'null' (i assume you mean empty) or it would not be entering the loop. Trim the line to make sure it's not just spaces
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Author Comment

by:redsar
ID: 9606040
yes, it's an empty
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 9606073
You can test for empty by a file size of zero.

File f = new File("input.txt");
boolean empty = (f.length() == 0);
System.out.println("File is empty? - " + empty);
0
 

Author Comment

by:redsar
ID: 9606118
thnaks CHEJ,
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 9606131
:-)
0
 

Author Comment

by:redsar
ID: 9606169
sorry, the problem is still there,
i want something like,
if the user select to open an account,
gets a customer Id,and other info, then write that to record.txt
and then if another user wanna open an account open the record.txt check whether the customer Id has already pick up by another user, if yes, error, if no, keep going...
0
 

Author Comment

by:redsar
ID: 9606306
i got it , thanks
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

An old method to applying the Singleton pattern in your Java code is to check if a static instance, defined in the same class that needs to be instantiated once and only once, is null and then create a new instance; otherwise, the pre-existing insta…
Introduction This article is the last of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article covers our test design approach and then goes through a simple test case example, how …
Viewers will learn about the regular for loop in Java and how to use it. Definition: Break the for loop down into 3 parts: Syntax when using for loops: Example using a for loop:
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …

733 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question