Update Text File

[meena latha]

Hi all.

I am using text file to store all my data's that are to be displayed in my jsp.I am reading my text file data using the below code.

  StringBuffer messageBuffer = new StringBuffer("");
        InputStream inStream = Thread.currentThread().getContextClassLoader().
        getResourceAsStream("DB.txt");
        BufferedReader reader  = new BufferedReader(new InputStreamReader(inStream));
        String line = null;
        
        while((line = reader.readLine())!=null){
        StringTokenizer tokenizer = new StringTokenizer(line,";");
        insertLaneToDB(tokenizer,standard);
        }   
                         

And inserting the values into a list.

 String Number = tokenizer.nextToken();
    String Id = tokenizer.nextToken();
    String name = tokenizer.nextToken();
    String rate = tokenizer.nextToken();
            
    Collect collect = new Collect(laneId,origin,destination,mode,rateType,rate,ibu);    
        List.add(lane);
   

here collect is a java class with getter and setter methods.

After this i am validating my data and if there is a error .
The error data is displayed in a text box where we can correct the value .

Now my problem is how do i save the corrected value to my text file.

For example,my text File has
23;1;North ;100
22;3;South;200
21;4;East;600
20;5;Weet;900

My fourth list has wrongly spelled name.
So this will appear in the text box and after correcting it how do i save this in text file.
The error date will appear in a jsp page with a save button in it.
This save button will call a method in Action Class.
I dont know what should i do in that action class to save the corrected value to the text file.

Any hit or clue or any help will be really appreciated.
Thanks
[ January 04, 2006: Message edited by: ramya jai ]

[Keith Lynn]

Because of the static nature of a text file, I think the only way to accomplish what you want is to read the entire file into memory, make the changes and write the file back. I would suggest doing this in a synchronized method.

[Stan James]

I often toss out this series of steps borrowed from an IBM mainframe timeshare system:

read original
modify in memory
write temp
rename original to backup
rename temp to original
erase backup

If somebody kicks the plug out of the wall at any time in there you still have a safe copy of the old and/or new data.