Question

currently i creating a java apps and no database required
that why i using text file to make it
the structure of file is like this

unique6id username identitynumber point

unique6id username identitynumber point

may i know how could i read and find match unique6id then update the correspond row of point ?

Sorry for lack of information
and here is the part i type is

public class Cust{
  string name;
  long idenid, uniqueid;
  int pts;
  customer(){}
  customer(string n,long ide, long uni, int pt){
        name = n;
        idenid = ide;
        uniqueid = uni;
        pts = pt;
  }


FileWriter fstream = new FileWriter("Data.txt", true);
            BufferedWriter fbw = new BufferedWriter(fstream);
                Cust newCust = new Cust();

                newCust.name = memUNTF.getText();
                newCust.ic = Long.parseLong(memICTF.getText());
                newCust.uniqueID = Long.parseLong(memIDTF.getText());
                newCust.pts= points;

            fbw.write(newCust.name + " " + newCust.ic + " " + newCust.uniqueID + " " + newCust.point);
            fbw.newLine();
            fbw.close();

this is the way i text in the data
then the result inside Data.txt is

spencerlim 900419129876 448505 0
Eugene 900419081234 586026 0

when user type in 586026 then it will grab row of eugene
bind into Cust
and update the pts (0 in this case, try to update it into other number eg. 30)

Thx for reply =D

Answer 1

Reading is pretty easy, but updating a text file in-place (ie without rewriting the whole file) is very awkward.

So, you have two options:

1. Read the whole file, make your changes, and then write the whole file to disk, overwriting the old version; this is quite easy, and will be fast enough for small files, but is not a good idea for very large files.

2. Use a format that is not a simple text file. A database would be one option (and bear in mind that there is one, Derby, built into the JDK); there are other ways of keeping simple key-value stores on disk (like a HashMap, but in a file), but there’s nothing built into the JDK.