How to replace a particular word by another word in a file in java?

Question

If you use fread to read a file of unknown size with a set buffer size of say 500 bytes, when you get to the end of the file you are likely to read a stub of 500 bytes of info and the eof marker.

And fread will not read that block and set and oef that can be read with feof. That is how I understand, so we can either use fseek to discover the file size and fread accordingly or use fstat?

Is this the proper approach?

Answer 1

There is a inbuilt function called replaceAll to do this in a sting. So steps would be to read whole file in a string apply the function replaceAll and write this new string in the file.

import java.io.*;

public class BTest
    {
     public static void main(String args[])
         {
         try
             {
             File file = new File("file.txt");
             BufferedReader reader = new BufferedReader(new FileReader(file));
             String line = "", oldtext = "";
             while((line = reader.readLine()) != null)
                 {
                 oldtext += line + "
";
             }
             reader.close();

             String newtext = oldtext.replaceAll("Ajay", "Salil");

             FileWriter writer = new FileWriter("file.txt");
             writer.write(newtext);writer.close();
         }
         catch (IOException ioe)
          {
             ioe.printStackTrace();
         }
     }
}