remove some specific characters from a set of files

Question

I have a folder holding a set of files, where some lines in each file contain a specific character as consisted of #, $ and %. How can I just remove these characters from those files while keeping other contents exactly the same as before. How to do that in Java?

Answer 1

Here's a solution with Java NIO.

Set<Path> paths = ... // get your file paths
// for each file
for (Path path : paths) { 
    String content = new String(Files.readAllBytes(path)); // read their content
    content = content.replace("$", "").replace("%", "").replace("#", ""); // replace the content in memory
    Files.write(path, content.getBytes(), StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING); // write the new content
}

I did not provide exception handling. Deal with that any way you want.

OR

If you are on Linux, use Java's ProcessBuilder to build a sed command to transform the content.

Answer 2

In pseudocode:

files = new File("MyDirectory").list();
for (file : files) {
  tempfile = new File(file.getName() + ".tmp", "w");
  do {
    buffer = file.read(some_block_size);
    buffer.replace(targetCharacters, replacementCharacter);
    tempfile.write(buffer);
  } while (buffer.size > 0);
  file.delete();
  tempfile.rename(file.getName());
}