JAVA FIND FILE RECURSIVELY CODE

It should search through a tree for a specified file.

using Java 8 we can locate a file in Java that is indicated by a starting path. One amazing feature of streams is that you can combine them with each other in various ways. In this tutorial we are going to learn about finding a file recursively in Java. But it becomes really interesting once we need to go deeper, recursively traversing subdirectories. Return FilenameUtils.getExtension(path.toString()).toLowerCase() collect(groupingBy(path -> getExt(path))) Įxtension + ' ' + matchingFiles.size())) filter(path -> !path.toFile().isDirectory()) it's fairly simple to count how many files I have in a directory per extension: The most important lesson here is: Files.list() returns a Stream - a value that we can pass around, compose, map, filter, etc. Remember that Files.list(Path) (new in Java 8) does not look into subdirectories - we'll fix that later. Luckily in Java 8 some of these issues can be addressed with streams:įinal File home = new File(FileUtils.getUserDirectoryPath()) įinal Stream files = Files.list(home.toPath()) Also we want to short-circuit searching to avoid unnecessary I/O. We would like to process files as they are discovered and lazily - by pipe-lining computation (but without clumsy visitor pattern). For example we don't want to build a list of all files because it will take a significant amount of time and memory before we can start processing it. sending it over networkĮvery use case above has a unique set of challenges. Looking for all files matching given pattern/property (also check out File.list(FilenameFilter)).Getting a complete list of all files for display purposes.I can imagine several use cases for recursive traversal of file system: It is probably the best counterexample of Open/Closed principle. Deleting a Directory (an empty directory) 11.4.10. () is rarely what we need, thus this method is neither reusable nor composable. Creates a new and empty directory in the default temp directory using the given prefix. Public void printFilesRecursively(final File folder) ĭidn't know File.listFiles() can return null, did ya? That's how it signals I/O errors, like if IOException never existed.

JAVA FIND FILE RECURSIVELY CODE

Similar code in Java would look something like this: Well, I didn't know the term recursion back then, but it worked. You can imagine how proud I was to discover I can actually call that procedure from itself to traverse file system recursively. First I came up with a procedure printing contents of a given directory. When I was learning programming, back in the days of Turbo Pascal, I managed to list files in directory using FindFirst, FindNext and FindClose functions. Turning recursive file system traversal into Stream

Java find file recursively