com.aspectran.core.util.FilenameUtils Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2023 The Aspectran Project
*
* Licensed 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 com.aspectran.core.util;
import java.io.File;
import java.io.IOException;
import java.util.Random;
import java.util.StringTokenizer;
/**
* Utility methods for General filename and filepath manipulation.
*
* This class defines six components within a filename
* (example C:\dev\project\file.txt):
*
* - the prefix - C:\
* - the path - dev\project\
* - the full path - C:\dev\project\
* - the name - file.txt
* - the base name - file
* - the extension - txt
*
*/
public class FilenameUtils {
private static final String NAME_SEPARATOR = "_";
private static final String EXTENSION_SEPARATOR = ".";
private static final char UNIX_SEPARATOR = '/';
private static final char WINDOWS_SEPARATOR = '\\';
private static final String EXTENSIONS_SEPARATORS = " ,;\t\n\r\f";
/**
* Gets the name minus the path from a full filename.
*
* This method will handle a file in either Unix or Windows format.
* The text after the last forward or backslash is returned.
*
* a/b/c.txt --> c.txt
* a.txt --> a.txt
* a/b/c --> c
* a/b/c/ --> ""
*
*
* The output will be the same irrespective of the machine that the code is running on.
* @param filename the filename to query, null returns null
* @return the name of the file without the path, or an empty string if none exists
*/
public static String getName(String filename) {
Assert.notNull(filename, "'filename' must not be null");
int index = indexOfLastSeparator(filename);
return filename.substring(index + 1);
}
/**
* Gets the base name, minus the full path and extension, from a full filename.
*
* This method will handle a file in either Unix or Windows format.
* The text after the last forward or backslash and before the last dot is returned.
*
* a/b/c.txt --> c
* a.txt --> a
* a/b/c --> c
* a/b/c/ --> ""
*
*
* The output will be the same irrespective of the machine that the code is running on.
* @param filename the filename to query, null returns null
* @return the name of the file without the path, or an empty string if none exists
*/
public static String getBaseName(String filename) {
return removeExtension(getName(filename));
}
/**
* Extract the file extension from the given filename.
*
* This method returns the textual part of the filename after the last dot.
* There must be no directory separator after the dot.
*
* foo.txt --> "txt"
* a/b/c.jpg --> "jpg"
* a/b.txt/c --> ""
* a/b/c --> ""
*
*
* The output will be the same irrespective of the machine that the code is running on.
* @param filename the filename to retrieve the extension of
* @return the extension of the file or an empty string if none exists
*/
public static String getExtension(String filename) {
Assert.notNull(filename, "'filename' must not be null");
int index = indexOfExtension(filename);
if (index == -1) {
return StringUtils.EMPTY;
} else {
return filename.substring(index + 1);
}
}
/**
* Removes the extension from a filename.
*
* This method returns the textual part of the filename before the last dot.
* There must be no directory separator after the dot.
*
* foo.txt --> foo
* a\b\c.jpg --> a\b\c
* a\b\c --> a\b\c
* a.b\c --> a.b\c
*
*
* The output will be the same irrespective of the machine that the code is running on.
* @param filename the filename to query, null returns null
* @return the filename minus the extension
*/
public static String removeExtension(String filename) {
Assert.notNull(filename, "'filename' must not be null");
int index = indexOfExtension(filename);
if (index == -1) {
return filename;
} else {
return filename.substring(0, index);
}
}
/**
* Returns the index of the last directory separator character.
*
* This method will handle a file in either Unix or Windows format.
* The position of the last forward or backslash is returned.
*
* The output will be the same irrespective of the machine that the code is running on.
* @param filename the filename to find the last path separator in, null returns -1
* @return the index of the last separator character, or -1 if there
* is no such character
*/
public static int indexOfLastSeparator(String filename) {
if (filename == null) {
return -1;
}
int lastUnixPos = filename.lastIndexOf(UNIX_SEPARATOR);
int lastWindowsPos = filename.lastIndexOf(WINDOWS_SEPARATOR);
return Math.max(lastUnixPos, lastWindowsPos);
}
/**
* Returns the index of the last extension separator character, which is a dot.
*
* This method also checks that there is no directory separator after the last dot.
* To do this it uses {@link #indexOfLastSeparator(String)} which will
* handle a file in either Unix or Windows format.
*
* The output will be the same irrespective of the machine that the code is running on.
* @param filename the filename to find the last path separator in, null returns -1
* @return the index of the last separator character, or -1 if there
* is no such character
*/
public static int indexOfExtension(String filename) {
if (filename == null) {
return -1;
}
int extensionPos = filename.lastIndexOf(EXTENSION_SEPARATOR);
int lastSeparator = indexOfLastSeparator(filename);
return (lastSeparator > extensionPos ? -1 : extensionPos);
}
/**
* Gets the path from a full filename.
* @param filename a full filename
* @return the path
*/
public static String getFullPath(String filename) {
if (filename == null) {
return null;
}
int index = indexOfLastSeparator(filename);
if (index < 0) {
return StringUtils.EMPTY;
}
return filename.substring(0, index);
}
/**
* Gets the path with end separator from a full filename.
* @param filename a full filename
* @return the path
*/
public static String getFullPathWithEndSeparator(String filename) {
if (filename == null) {
return null;
}
int index = indexOfLastSeparator(filename);
if (index < 0) {
return StringUtils.EMPTY;
}
return filename.substring(0, index + 1);
}
/**
* Checks whether the extension of the filename is valid.
* The extension check is case-sensitive on all platforms.
* @param filename the filename to query, null returns false
* @param allowedFileExtensions the allowed file extensions
* @param deniedFileExtensions the denied file extensions
* @return true if is valid file extension; false otherwise
*/
public static boolean isValidFileExtension(String filename, String allowedFileExtensions, String deniedFileExtensions) {
if (filename == null) {
return false;
}
String ext = getExtension(filename).toLowerCase();
if (allowedFileExtensions != null && !allowedFileExtensions.isEmpty()) {
if (ext.length() == 0) {
return false;
}
StringTokenizer st = new StringTokenizer(allowedFileExtensions.toLowerCase(), EXTENSIONS_SEPARATORS);
while (st.hasMoreTokens()) {
String ext2 = st.nextToken();
if (ext.equals(ext2)) {
return true;
}
}
return false;
}
if (deniedFileExtensions != null && !deniedFileExtensions.isEmpty()) {
if (ext.length() == 0) {
return true;
}
StringTokenizer st = new StringTokenizer(deniedFileExtensions.toLowerCase(), EXTENSIONS_SEPARATORS);
while (st.hasMoreTokens()) {
String ext2 = st.nextToken();
if (ext.equals(ext2)) {
return false;
}
}
return true;
}
return true;
}
/**
* Returns a file name that does not overlap in the specified directory.
* If a duplicate file name exists, it is returned by appending a number after the file name.
* @param srcFile the file to seek
* @return a unique file
* @throws IOException if failed to obtain a unique file
*/
public static File generateUniqueFile(File srcFile) throws IOException {
return generateUniqueFile(srcFile, EXTENSION_SEPARATOR);
}
/**
* Returns a file name that does not overlap in the specified directory.
* If a duplicate file name exists, it is returned by appending a number after the file name.
* @param srcFile the file to seek
* @param extSeparator the file extension separator
* @return a unique file
* @throws IOException if failed to obtain a unique file
*/
public static File generateUniqueFile(File srcFile, String extSeparator) throws IOException {
Assert.notNull(srcFile, "'srcFile' must not be null");
String path = getFullPath(srcFile.getCanonicalPath());
String name = removeExtension(srcFile.getName());
String ext = getExtension(srcFile.getName());
String newName;
if (StringUtils.hasLength(ext)) {
newName = name + extSeparator + ext;
} else {
newName = name;
}
File destFile = new File(path, newName);
int count = 0;
while (destFile.exists()) {
count++;
if (ext != null && !ext.isEmpty()) {
newName = name + NAME_SEPARATOR + count + extSeparator + ext;
} else {
newName = name + NAME_SEPARATOR + count;
}
destFile = new File(path, newName);
}
return (count == 0 ? srcFile : destFile);
}
/**
* Creates and returns a system-safe file name without duplicates in the specified directory.
* If there is a duplicate file name, a number is added after the file name and returned.
* File extensions are separated by '.' character.
*
* ex) 1111111111_1.txt
*
* @param file the file to seek
* @return a unique file
* @throws IOException if failed to obtain a unique file
*/
public static File generateSafetyUniqueFile(File file) throws IOException {
return generateSafetyUniqueFile(file, EXTENSION_SEPARATOR);
}
/**
* Creates and returns a system-safe file name without duplicates in the specified directory.
* If there is a duplicate file name, a number is added after the file name and returned.
* If the file extension separator is specified as '_', the file name can be obtained
* in the following format.
*
* ex) 1111111111_txt
*
* @param file the file to seek
* @return a unique file
* @param extSeparator the file extension separator
* @throws IOException if failed to obtain a unique file
*/
public static File generateSafetyUniqueFile(File file, String extSeparator) throws IOException {
String path = file.getCanonicalPath();
String ext = getExtension(path);
String prefix = Long.toString(System.currentTimeMillis());
Random rnd = new Random();
String suffix = Integer.toString(rnd.nextInt(9999));
String fullName;
if (ext != null && !ext.isEmpty()) {
fullName = prefix + NAME_SEPARATOR + suffix + extSeparator + ext;
} else {
fullName = prefix + NAME_SEPARATOR + suffix;
}
File file2 = new File(getFullPath(path), fullName);
return generateUniqueFile(file2, NAME_SEPARATOR);
}
/**
* Recovers the extension from a unique file name.
* @param uniqueFilename a unique file name
* @return file name with recovered extension
*/
public static String recoverExtension(String uniqueFilename) {
return StringUtils.replaceLast(uniqueFilename, NAME_SEPARATOR, EXTENSION_SEPARATOR);
}
}