FileUtilities

The FileUtilities class contains many utility methods to deals with Files and URLs. The FileUtilities2 class contains also some additional utility methods.

Handling URL paths

Several methods allow to handle URL paths and construct children URLs from parent URLs. For example:

• The FileUtilities.getParentURL(URL) method allows to get the parent URL from an URL
• The FileUtilities.getChildURL(URL, String) method allows to get the child URL from a parent URL and a path (also escaping characters if necessary). The FileUtilities.getChildURL(URL, String, boolean) method will also check if the resulting URL exists and return null if it does not

Getting an absolute URL

The FileUtilities.getAbsoluteURL(URL, String) method will return the absolute URL knowing the parent URL and the relative of absolute path.

If the relative Path is already absolute, the parent base URL will not be used, else the resulting URL will be constructed using the base URL and the relativePath.

Getting the absolute path of an URL

Several methods allow to get the absolute path of a relative path from a parent directory or URL, with the appropriate separator for the platform. For example:

• The FileUtilities.getAbsolutePath(URL, String) method will return the absolute path knowing the parent URL and the relative of absolute path

If the relative Path is already absolute, the parent base URL will not be used, else the path will be constructed using the base URL and the relativePath.

For example:

   URL parentURL = new URL("file:/L:/WRK/toto/test/resources");
   String path = FileUtilities.getAbsolutePath(parentURL, "myFile.xml");
   // path will be "L:\WRK\toto\test\resources\myFile.xml" on Windows

   URL parentURL = new URL("file:/L:/WRK/my/files");
   String path = FileUtilities.getAbsolutePath(parentURL, "L:/WRK/toto/test/resources/myFile.xml");
   // path will be "L:\WRK\toto\test\resources\myFile.xml" on Windows

Removing the relative delimiters of a path

The FileUtilities.makeAbsoluteURLPath(String) will remove the relative delimiters ( .. and .) from a path and return the associated URL.

For example:

   URL url = FileUtilities.makeAbsoluteURLPath("L:/WRK/Java/resources/MyFile.xml");
   // url will be "file:L:/WRK/Java/resources/MyFile.xml"

   url = FileUtilities.makeAbsoluteURLPath("L:/WRK/Java/resources/../MyFile.xml");
   // url will be "file:L:/WRK/Java/MyFile.xml"

   url = FileUtilities.makeAbsoluteURLPath("L:/WRK/Java/resources/./MyFile.xml");
   // url will be "file:L:/WRK/Java/resources/MyFile.xml"

Detecting absolute paths

The FileUtilities.isAbsolute(String) method will return true if a file path is absolute.

The FileUtilities.isAbsoluteURI(String) method will return true if an URI is absolute.

Handling escape sequences in URL paths

The methods in this class will try to:

• Convert space characters to their equivalent "%20" escape sequence when handling URL paths
• Keep "%20" escape sequence characters when handling URL paths
• Property convert them to space characters when converting to files

Checking file or URL existence

Checking file existence

Two methods allow to check for file existence:

• FileUtilities.exist(File) check if the File exists
• FileUtilities.exist(File, int) check if the File exists, taking into account options to set how the check is performed

The FileUtilities.exist(File, int) method use the following options for the check:

• FileUtilities.OPTION_FILEEXIST_READ check if it is possible to read the content of the File
• FileUtilities.OPTION_FILEEXIST_LENGTH check if the length of the file is not 0

Checking URL existence

Two methods allow to check for file existence:

• FileUtilities.exist(URL) check if the URL exists
• FileUtilities.exist(URL, int) check if the URL exists, taking into account options to set how the check is performed

The second method can use the following options for the check:

• FileUtilities.OPTION_FILEEXIST_READ check if it is possible to read the content of the URL
• FileUtilities.OPTION_FILEEXIST_LENGTH check if the length of the file or URL is not 0
• FileUtilities.OPTION_FILEEXIST_SKIP_QUERIES will consider that an URL does not exist if the query part of the URL is not null
• FileUtilities.OPTION_FILEEXIST_SKIP_PHP will consider that an URL does not exist if the URL points to a PHP resource
• FileUtilities.OPTION_FILEEXIST_HTTP_FORCETRUE will consider that an URL exist if the URL points to a http or https resource.Note that if the OPTION_FILEEXIST_SKIP_QUERIES or OPTION_FILEEXIST_SKIP_PHP options are set, then the URL will still be considered as not existing even if the OPTION_FILEEXIST_HTTP_FORCETRUE is set

These options can be associated. For example:

   int option = FileUtilities.OPTION_FILEEXIST_SKIP_QUERIES + OPTION_FILEEXIST_SKIP_PHP;
   boolean exists = FileUtilities.exist(theUrl);

Will check if the URL exist, but will consider that the URL does not exist if:

• The query part of the URL is not null
• Or the URL points to a php resource

Checking if an URL is found

The FileUtilities.isURLFound(URL, int) method allows to check if it is possible to access an URL. Several options can be combined:

• FileUtilities.OPTION_ACCEPT301CODE will accept 301 (Moved Permanently redirect) and 308 (Permanent Redirect redirect status) return codes
• FileUtilities.OPTION_FOLLOWREDIRECT will follow redirect links
• FileUtilities.OPTION_FILEEXIST_SKIP_QUERIES will consider that an URL does not exist if the query part of the URL is not null
• FileUtilities.OPTION_FILEEXIST_SKIP_PHP will consider that an URL does not exist if the URL points to a PHP resource

It is possible to add a timeOut to check for the URL existance. Also note that special versions of this method allow to use a Proxy and a user agent to get the URL content.

Getting a File from a path

Several methods allow to get a File from a path:

• The FileUtilities.getFile(String) method will return the File corresponding to the path if the path is absolute, or the File corresponding to a child of the user directory. If the resulting File does not exist, the method will return null
• The FileUtilities.getFile(String, boolean) method will return the File corresponding to the path if the path is absolute, or the File corresponding to a child of the user directory. The method will return null if the resulting File does not exist if the second argument is true
• The FileUtilities.getFile(File, String) method will return the File corresponding to the path if the path is absolute, or the File corresponding to a child of the first argument directory (or the user directory if the first argument is null). If the resulting File does not exist, the method will return null
• The FileUtilities.getFile(File, String, boolean) method will return the File corresponding to the path if the path is absolute, or the File corresponding to a child of the first argument directory (or the user directory if the first argument is null). The method will return null if the resulting File does not exist if the second argument is true

For example:

   File dir = new File("C:/my/directory");
   File theFile = FileUtilities.getFile("C:/thedirectory/myfile.txt"); // will return the File C:/thedirectory/myfile.txt
   File theFile2 = FileUtilities.getFile("myfile.txt"); // will return the File C:/my/directory/myfile.txt

Getting the child of a parent URL

Several methods allow to get a child URL, knowing the parent URL and the relative path. Note that if the path is absolute, then ii will return the URL corresponding with the path.

Getting the child of a parent URL without options

The FileUtilities.getChildURL(URL, String) method will get all a child URL, knowing the parent URL and the relative path.

Note that:

• The method will not filter URLs corresponding to not existing resources
• The resulting URL will escape spaces in file paths by a "%20" String

Getting the child of a parent URL with options

The FileUtilities.getChildURL(URL, String, int) method will get all a child URL, knowing the parent URL and the relative path. Several options can be combined:

• FileUtilities.OPTION_CHILDURL_ESCAPE will escape spaces in file paths by a "%20" String
• FileUtilities.OPTION_CHILDURL_FILTEREXIST will filter any URLs corresponding to not existing resources
• FileUtilities.OPTION_CHILDURL_FILTEREXIST_FILE will filter non http URLs corresponding to not existing resources
• FileUtilities.OPTION_CHILDURL_FILTEREXIST_HTTP will filter URLs http corresponding to not existing resources

Getting all the direct children of a parent URL

The FileUtilities.getChildren(URL, boolean) method will get all the direct children URLs for a parent URL, including in the case where the parent URL is a zip or jar file.

Getting the URL of an entry in an archive

The FileUtilities.getJarEntryURL(URL, String) method allow to get the URL of an entry in a Jar or Zip file.

For example, suppose that we have the following zip file:

      zipfile.zip
         - directchild.txt
         - directory
            - file1.txt

To get the URL for the directchild.txt entry, we can do:

   File zipFile = new File("zipfile.zip");
   URL url = zipFile.toURI().toURL();
   URL childURL = FileUtilities.getJarEntryURL(url, "directchild.txt");

To get the URL for the file1.txt entry, we can do:

   File zipFile = new File("zipfile.zip");
   URL url = zipFile.toURI().toURL();
   URL childURL = FileUtilities.getJarEntryURL(url, "directory/file1.txt");

Getting a compatible file

Several methods allow to get a file, making sure that it have a desired extension or one extensions among several. If the input file has the desired extension, it will be returned. If not, the method will return a file with the same path but with the desired extension.

• The FileUtilities.getCompatibleFile(File, String) returns a file with a specified extension
• The FileUtilities.getCompatibleFile(File, Set, String) and FileUtilities.getCompatibleFile(File, String[], String) will return a File with one of the specified extensions

Examples

For example:

   File txtfile = new File("C:/my/file.txt");
   File resulttxt = FileUtilities.getCompatibleFile(txtfile, "txt"); // will return the same C:/my/file.txt file
   resulttxt = FileUtilities.getCompatibleFile(txtfile, "png"); // will return the C:/my/file.png file
      
   txtfile = new File("C:/my/file.TXT");
   File resulttxt = FileUtilities.getCompatibleFile(txtfile, "txt"); // will return the same C:/my/file.TXT file      
      
   File file = new File("C:/my/thefile");
   File resultjpg = FileUtilities.getCompatibleFile(txtfile, "jpg"); // will return the C:/my/file.jpg file

Detecting if a file or URL is an archive

The FileUtilities.isArchive(URL) and FileUtilities.isArchive(File) methods detect if a File is an archive. Note that it does this by reading the first bytes of the File, so it does not rely on the File extension.