Find files in a folder using Java

Question

What I need to do if Search a folder say C:\\example

I then need to go through each file and check to see if it matches a few start characters so if fil

Answer 1

You can use a FilenameFilter, like so:

File dir = new File(directory);

File[] matches = dir.listFiles(new FilenameFilter()
{
  public boolean accept(File dir, String name)
  {
     return name.startsWith("temp") && name.endsWith(".txt");
  }
});

Answer 2

I know, this is an old question. But just for the sake of completeness, the lambda version.

File dir = new File(directory);
File[] files = dir.listFiles((dir1, name) -> name.startsWith("temp") && name.endsWith(".txt"));

Answer 3

Consider Apache Commons IO, it has a class called FileUtils that has a listFiles method that might be very useful in your case.

Answer 4

What you want is File.listFiles(FileNameFilter filter).

That will give you a list of the files in the directory you want that match a certain filter.

The code will look similar to:

// your directory
File f = new File("C:\\example");
File[] matchingFiles = f.listFiles(new FilenameFilter() {
    public boolean accept(File dir, String name) {
        return name.startsWith("temp") && name.endsWith("txt");
    }
});

Answer 5

Appache commons IO various

FilenameUtils.wildcardMatch

See Apache javadoc here. It matches the wildcard with the filename. So you can use this method for your comparisons.

Answer 6

As of Java 1.8, you can use Files.list to get a stream:

Path findFile(Path targetDir, String fileName) throws IOException {
    return Files.list(targetDir).filter( (p) -> {
        if (Files.isRegularFile(p)) {
            return p.getFileName().toString().equals(fileName);
        } else {
            return false;
        }
    }).findFirst().orElse(null);
}