Commons IO

Links

Maven 2 Dependency

<dependency>
  <groupId>commons-io</groupId>
  <artifactId>commons-io</artifactId>
  <version>1.4</version>
</dependency>

Directory Walker

Sample project in Subversion: sample-commons-directory-walker

Note: Also see FileUtils, List Files below.

FilenameUtils

Extension

getExtension

import org.apache.commons.io.FilenameUtils;
String extension = FilenameUtils.getExtension(file.getName());

Name

getName Gets the name minus the path from a full filename.

import org.apache.commons.io.FilenameUtils;
final String fileName = FilenameUtils.getName(file.getAbsolutePath());

getBaseName Gets the base name, minus the full path and extension, from a full filename.

import org.apache.commons.io.FilenameUtils;
final String name = FilenameUtils.getBaseName(file.getAbsolutePath());

FileUtils

Import:

import org.apache.commons.io.FileUtils;

Copy Folder (and it’s contents)

copyDirectory

copyDirectory

import org.apache.commons.io.FileUtils;

FileUtils.copyDirectory(sourceFolder, destinationFolder);

Note: To ignore svn folders:

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.filefilter.FileFilterUtils;

FileUtils.copyDirectory(configFolder, applicationConfigFolder,
    FileFilterUtils.makeSVNAware(null));

Copy File

copyFile

copyFile

FileUtils.copyFile(sourceFile, destinationFile);

Copy File to Folder

copyFileToDirectory

copyFileToDirectory

FileUtils.copyFileToDirectory(fromFile, toFolder);

Copy Folder

// copy one folder and its contents into another
FileUtils.copyDirectoryToDirectory(file1, file2);

Delete Folder

deleteDirectory

FileUtils.deleteDirectory(folder);

Line Iterator

BufferedReader reader = null;
try {
    reader = new BufferedReader(new FileReader(file));
    LineIterator it = IOUtils.lineIterator(reader);
    String line;
    while (it.hasNext()) {
        line = it.nextLine();
        }
    }
} finally {
    IOUtils.closeQuietly(reader);
}

List Files

// return the list of xml and text files in the specified folder and any subfolders
Collection<File> c1 = FileUtils.listFiles(file1, { "xml", "txt" }, true);

Note: I haven’t tested this.

Move File

moveFileToDirectory:

final File moveTo = new File(file.getParent(), "done");
FileUtils.moveFileToDirectory(file, moveTo, true);

true tells the moveFileToDirectory to create the destination folder.

Read a File

import org.apache.commons.io.FileUtils;
return FileUtils.readFileToString(new File("file_name.txt"));

Touch

import org.apache.commons.io.FileUtils;
FileUtils.touch(new File(fileName));

IOUtils

IOUtils

closeQuietly

Close a stream ignoring nulls and exceptions:

InputStream is = null;
try {
    is = new BufferedInputStream(new FileInputStream(new File(resource
            .getPath())));
} finally {
    IOUtils.closeQuietly(is);
}

readLines

readLines. Get the contents of a file as a list of Strings, one entry per line:

BufferedReader in = null;
try {
    in = new BufferedReader(new FileReader(fileName));
    final List<String> result = IOUtils.readLines(in);
    return result;
} finally {
    IOUtils.closeQuietly(in);
}