FileUtils.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.tomcat.util.http.fileupload;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
/**
* General file manipulation utilities.
* <p>
* Facilities are provided in the following areas:
* <ul>
* <li>writing to a file
* <li>reading from a file
* <li>make a directory including parent directories
* <li>copying files and directories
* <li>deleting files and directories
* <li>converting to and from a URL
* <li>listing files and directories by filter and extension
* <li>comparing file content
* <li>file last changed date
* <li>calculating a checksum
* </ul>
* <p>
* Note that a specific charset should be specified whenever possible.
* Relying on the platform default means that the code is Locale-dependent.
* Only use the default if the files are known to always use the platform default.
* <p>
* Origin of code: Excalibur, Alexandria, Commons-Utils
*/
public class FileUtils {
/**
* Instances should NOT be constructed in standard programming.
*/
public FileUtils() {
super();
}
//-----------------------------------------------------------------------
/**
* Deletes a directory recursively.
*
* @param directory directory to delete
* @throws IOException in case deletion is unsuccessful
* @throws IllegalArgumentException if {@code directory} does not exist or is not a directory
*/
public static void deleteDirectory(final File directory) throws IOException {
if (!directory.exists()) {
return;
}
if (!isSymlink(directory)) {
cleanDirectory(directory);
}
if (!directory.delete()) {
final String message =
"Unable to delete directory " + directory + ".";
throw new IOException(message);
}
}
/**
* Cleans a directory without deleting it.
*
* @param directory directory to clean
* @throws IOException in case cleaning is unsuccessful
* @throws IllegalArgumentException if {@code directory} does not exist or is not a directory
*/
public static void cleanDirectory(final File directory) throws IOException {
if (!directory.exists()) {
final String message = directory + " does not exist";
throw new IllegalArgumentException(message);
}
if (!directory.isDirectory()) {
final String message = directory + " is not a directory";
throw new IllegalArgumentException(message);
}
final File[] files = directory.listFiles();
if (files == null) { // null if security restricted
throw new IOException("Failed to list contents of " + directory);
}
IOException exception = null;
for (File file : files) {
try {
forceDelete(file);
} catch (IOException ioe) {
exception = ioe;
}
}
if (null != exception) {
throw exception;
}
}
//-----------------------------------------------------------------------
/**
* Deletes a file. If file is a directory, delete it and all sub-directories.
* <p>
* The difference between File.delete() and this method are:
* <ul>
* <li>A directory to be deleted does not have to be empty.</li>
* <li>You get exceptions when a file or directory cannot be deleted.
* (java.io.File methods returns a boolean)</li>
* </ul>
*
* @param file file or directory to delete, must not be {@code null}
* @throws NullPointerException if the directory is {@code null}
* @throws FileNotFoundException if the file was not found
* @throws IOException in case deletion is unsuccessful
*/
public static void forceDelete(final File file) throws IOException {
if (file.isDirectory()) {
deleteDirectory(file);
} else {
final boolean filePresent = file.exists();
if (!file.delete()) {
if (!filePresent) {
throw new FileNotFoundException("File does not exist: " + file);
}
final String message =
"Unable to delete file: " + file;
throw new IOException(message);
}
}
}
/**
* Schedules a file to be deleted when JVM exits.
* If file is directory delete it and all sub-directories.
*
* @param file file or directory to delete, must not be {@code null}
* @throws NullPointerException if the file is {@code null}
* @throws IOException in case deletion is unsuccessful
*/
public static void forceDeleteOnExit(final File file) throws IOException {
if (file.isDirectory()) {
deleteDirectoryOnExit(file);
} else {
file.deleteOnExit();
}
}
/**
* Schedules a directory recursively for deletion on JVM exit.
*
* @param directory directory to delete, must not be {@code null}
* @throws NullPointerException if the directory is {@code null}
* @throws IOException in case deletion is unsuccessful
*/
private static void deleteDirectoryOnExit(final File directory) throws IOException {
if (!directory.exists()) {
return;
}
directory.deleteOnExit();
if (!isSymlink(directory)) {
cleanDirectoryOnExit(directory);
}
}
/**
* Cleans a directory without deleting it.
*
* @param directory directory to clean, must not be {@code null}
* @throws NullPointerException if the directory is {@code null}
* @throws IOException in case cleaning is unsuccessful
*/
private static void cleanDirectoryOnExit(final File directory) throws IOException {
if (!directory.exists()) {
String message = directory + " does not exist";
throw new IllegalArgumentException(message);
}
if (!directory.isDirectory()) {
String message = directory + " is not a directory";
throw new IllegalArgumentException(message);
}
File[] files = directory.listFiles();
if (files == null) { // null if security restricted
throw new IOException("Failed to list contents of " + directory);
}
IOException exception = null;
for (File file : files) {
try {
forceDeleteOnExit(file);
} catch (IOException ioe) {
exception = ioe;
}
}
if (null != exception) {
throw exception;
}
}
/**
* Makes a directory, including any necessary but nonexistent parent
* directories. If a file already exists with specified name but it is
* not a directory then an IOException is thrown.
* If the directory cannot be created (or does not already exist)
* then an IOException is thrown.
*
* @param directory directory to create, must not be {@code null}
* @throws NullPointerException if the directory is {@code null}
* @throws IOException if the directory cannot be created or the file already exists but is not a directory
*/
public static void forceMkdir(final File directory) throws IOException {
if (directory.exists()) {
if (!directory.isDirectory()) {
final String message =
"File "
+ directory
+ " exists and is "
+ "not a directory. Unable to create directory.";
throw new IOException(message);
}
} else {
if (!directory.mkdirs()) {
// Double-check that some other thread or process hasn't made
// the directory in the background
if (!directory.isDirectory()) {
final String message =
"Unable to create directory " + directory;
throw new IOException(message);
}
}
}
}
/**
* Makes any necessary but nonexistent parent directories for a given File. If the parent directory cannot be
* created then an IOException is thrown.
*
* @param file file with parent to create, must not be {@code null}
* @throws NullPointerException if the file is {@code null}
* @throws IOException if the parent directory cannot be created
* @since 2.5
*/
public static void forceMkdirParent(final File file) throws IOException {
final File parent = file.getParentFile();
if (parent == null) {
return;
}
forceMkdir(parent);
}
/**
* Determines whether the specified file is a Symbolic Link rather than an actual file.
* <p>
* Will not return true if there is a Symbolic Link anywhere in the path,
* only if the specific file is.
* <p>
* <b>Note:</b> the current implementation always returns {@code false} if
* the system is detected as Windows using
* {@link File#separatorChar} == '\\'
*
* @param file the file to check
* @return true if the file is a Symbolic Link
* @throws IOException if an IO error occurs while checking the file
* @since 2.0
*/
public static boolean isSymlink(File file) throws IOException {
if (file == null) {
throw new NullPointerException("File must not be null");
}
//FilenameUtils.isSystemWindows()
if (File.separatorChar == '\\') {
return false;
}
File fileInCanonicalDir = null;
if (file.getParent() == null) {
fileInCanonicalDir = file;
} else {
File canonicalDir = file.getParentFile().getCanonicalFile();
fileInCanonicalDir = new File(canonicalDir, file.getName());
}
if (fileInCanonicalDir.getCanonicalFile().equals(fileInCanonicalDir.getAbsoluteFile())) {
return false;
} else {
return true;
}
}
}