Word replacement from a folder with multiple files using java

Question

I have a java program that will do a word replacement for a single file by providing a path. I want to change this java program so it can be excused in a folder with many files. Once it make the changes it writes back to the file. I'm stuck on how to do this. I know I need a loop to go over the file. Question: What java api should I be using for reading from the folders Here is my code:

import java.io.* ;
public class Replace{
    public static void main(String[] args) {
     File file = new File("My_text.txt");


         try
             {
             BufferedReader reader = new BufferedReader(new FileReader(file));

             String line = "", oldtext = "";
             while((line = reader.readLine()) != null)
                 {
                 oldtext += line + "\r\n";
             }
             reader.close();

             String replacedtext  = oldtext.replaceAll("<eol> ", "");
             replacedtext = replacedtext.replaceAll("<eos> ", "");
             replacedtext = replacedtext.replaceAll(" \\.", ".");
             replacedtext = replacedtext.replaceAll(" \\,", ",");
             //replacedtext = replacedtext.replaceAll("  ", "");
             replacedtext = replacedtext.replaceAll(" \\'s", "'s");

             FileWriter writer = new FileWriter("My_text.txt");
             writer.write(replacedtext);


             writer.close();

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

Answer 1

This will do the trick. You can get all files with method listFiles() which you can call on File from java.io.

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class Replace {
    public static void main(String[] args) {
        File folder = new File("C:/PathToYourFolder");
        File[] listOfFiles = folder.listFiles();
        for(File file : listOfFiles) {
            replaceText(file);
        }
    }

    public static void replaceText(File file) {

        try {
            BufferedReader reader = new BufferedReader(new FileReader(file));

            String line = "", oldtext = "";
            while ((line = reader.readLine()) != null) {
                oldtext += line + "\r\n";
            }
            reader.close();

            String replacedtext = oldtext.replaceAll("<eol> ", "");
            replacedtext = replacedtext.replaceAll("<eos> ", "");
            replacedtext = replacedtext.replaceAll(" \\.", ".");
            replacedtext = replacedtext.replaceAll(" \\,", ",");
            // replacedtext = replacedtext.replaceAll(" ", "");
            replacedtext = replacedtext.replaceAll(" \\'s", "'s");

            FileWriter writer = new FileWriter(file);
            writer.write(replacedtext);

            writer.close();

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

Answer 2

First move your code into a method that can take a file name as input and make replacements within that file. Then write some code using file.listFiles() to recurse over all files in a directory and process them. Something like:

public static void main(String[] args) {
  String myDir = "C:\Path\To\Directory";
  recurseOnFile(new File(myDir));
}

private static void recurseOnFile(File passedFile) {
  if (passedFile.isFile()) {
    replaceInFile(passedFile);
  }else if (passedFile.isDirectory()) {
     File[] listOfFiles = passedFile.listFiles();
    for (File inDir : listOfFiles) {
      recurseOnFile(inDir);
    }
  }
}

private static void replaceInFile(File file) {
  //put your current code for replacing in one file here
}

This will start at a location, and if that location is a file it will process it. If the location is a directory it will process all of the files in the directory. If the directory contains other directories, it will continue to recursively process until all files in all subfolders of the original location have been processed.