public class File
- Object
- File
This class provides a similar API to
java.io.File making it almost into a “drop in” replacement.
It is placed in a different package because it is incompatible to java.io.File by definition. It is useful
in getting some simple code to work without too many changesNested types
interface File.FilenameFilter | Interface to filter filenames. |
interface File.FileFilter | Interface for filtering files. |
Fields
public static final char separatorChar = '/' | |
public static final String separator = "/" |
Constructors
public File(URI uri) | Creates a new File object from the given URI |
public File(String path) | Creates a new file object with given path. |
public File(String dir, String file) | Creates a new file object in a given directory. |
public File(File parent, String path) | Creates a new file in the given parent directory, and subpath. |
Methods
public static File[] listRoots() | List the file system roots. |
public static File createTempFile(String prefix, String suffix)
throws IOException | Creates a temporary file. |
public String getName() | Returns the file name. |
public String getParent() | Gets the parent directory path. |
public File getParentFile() | Returns the file object for the parent directory. |
public String getPath() | Gets the path to the file. |
public boolean isAbsolute() | Checks if the path is absolute. |
public String getAbsolutePath() | Gets the absolute path of the file as a string, |
public File getAbsoluteFile() | Gets the absolute file - which is always itself, since #isAbsolute() always returns true. |
public boolean exists() | Checks if the file described by this object exists on the file system. |
public boolean isDirectory() | Checks if this file is a directory. |
public boolean isFile() | Checks if this file object represents a regular file. |
public boolean isHidden() | Checks if this is a hidden file. |
public long lastModified() | Gets the last modified time as a unix timestamp in milliseconds. |
public long length() | Gets the file size in bytes. |
public boolean createNewFile()
throws IOException | Creates this file as a new blank file in the file system. |
public boolean delete() | Deletes the file described by this object on the file system. |
public String[] list() | Returns the list of child files of this directory. |
public String[] list(File.FilenameFilter filter) | Returns list of child files of this directory |
public File[] listFiles() | Gets a list of child files of this directory. |
public File[] listFiles(File.FilenameFilter ff) | Gets a list of child files of this directory, filtered using the provided filter. |
public File[] listFiles(File.FileFilter ff) | Gets a list of child files of this directory, filtering them using the provided filter. |
public boolean mkdir() | Attempts to make the directory described by this object. |
public boolean mkdirs() | Attempts to make the directory (and all parent directories) of this object. |
public boolean renameTo(File f) | Renames the file to the provided file object. |
public boolean canExecute() | Checks if this file is executable. |
public long getTotalSpace() | Returns the total space on the root file system. |
public long getFreeSpace() | Gets the free space on the root file system. |
public long getUsableSpace() | Gets the usable space on this file system. |
public boolean equals(Object o) | Checks if the given object refers to the same file. |
public int hashCode() | Returns a hash code value for the object. |
public String toString() | Returns a string representation of the object. |
public URL toURL()
throws MalformedURLException | Converts this file to a URL. |
public URI toURI()
throws URISyntaxException | Converts this file to a URI. |
Inherited methods
Field details
separatorChar
public static final char separatorChar = '/'separator
public static final String separator = "/"Constructor details
File
public File(URI uri)Creates a new File object from the given URI
File
public File(String path)Creates a new file object with given path. Paths that do not begin with the “file:” prefix
will automatically be prefixed with the app home path.
Parameters
pathString- The path of the file. Relative or absolute.
File
public File(String dir, String file)Creates a new file object in a given directory.
Parameters
dirString- The parent directory path.
fileString- The file name
File
public File(File parent, String path)Creates a new file in the given parent directory, and subpath.
Parameters
parentFile- The parent directory.
pathString- The subpath, beginning with the parent directory.
Method details
listRoots
public static File[] listRoots()List the file system roots.
createTempFile
public static File createTempFile(String prefix, String suffix)
throws IOExceptionCreates a temporary file.
Parameters
prefixString- The file name prefix.
suffixString- The file name suffix
Returns
The resulting temporary file.
Throws
getName
public String getName()Returns the file name.
Returns
The file name.
getParent
public String getParent()Gets the parent directory path.
Returns
The parent directory path.
getParentFile
public File getParentFile()Returns the file object for the parent directory.
getPath
public String getPath()Gets the path to the file.
isAbsolute
public boolean isAbsolute()Checks if the path is absolute. This always returns true as all File objects
use absolute paths - even if they were created with relative paths. Relative paths are automatically
prefixed with the app home directory path.
getAbsolutePath
public String getAbsolutePath()Gets the absolute path of the file as a string,
getAbsoluteFile
public File getAbsoluteFile()Gets the absolute file - which is always itself, since
#isAbsolute() always returns true.Returns
The same file object.
exists
public boolean exists()Checks if the file described by this object exists on the file system.
isDirectory
public boolean isDirectory()Checks if this file is a directory.
isFile
public boolean isFile()Checks if this file object represents a regular file.
isHidden
public boolean isHidden()Checks if this is a hidden file.
lastModified
public long lastModified()Gets the last modified time as a unix timestamp in milliseconds.
length
public long length()Gets the file size in bytes.
Returns
The file size in bytes.
createNewFile
public boolean createNewFile()
throws IOExceptionCreates this file as a new blank file in the file system.
Returns
True if it succeeds.
Throws
delete
public boolean delete()Deletes the file described by this object on the file system.
Returns
True if delete succeeds.
list
public String[] list()Returns the list of child files of this directory.
list
public String[] list(File.FilenameFilter filter)Returns list of child files of this directory
listFiles
public File[] listFiles()Gets a list of child files of this directory.
listFiles
public File[] listFiles(File.FilenameFilter ff)Gets a list of child files of this directory, filtered using the provided filter.
Parameters
ffFile.FilenameFilter- The filter to use.
listFiles
public File[] listFiles(File.FileFilter ff)Gets a list of child files of this directory, filtering them using the provided filter.
Parameters
ffFile.FileFilter- The filter to use to filter output.
mkdir
public boolean mkdir()Attempts to make the directory described by this object.
Returns
True on success.
mkdirs
public boolean mkdirs()Attempts to make the directory (and all parent directories) of this object.
Returns
True on success.
renameTo
public boolean renameTo(File f)Renames the file to the provided file object.
Parameters
fFile- The file object that we are renaming the file to.
Returns
True on success.
canExecute
public boolean canExecute()Checks if this file is executable.
getTotalSpace
public long getTotalSpace()Returns the total space on the root file system.
getFreeSpace
public long getFreeSpace()Gets the free space on the root file system.
getUsableSpace
public long getUsableSpace()Gets the usable space on this file system.
equals
public boolean equals(Object o)Checks if the given object refers to the same file.
hashCode
public int hashCode()Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.
The general contract of hashCode is: Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables.
As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)
toString
public String toString()Returns a string representation of the object. In general, the toString method returns a string that “textually represents” this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.
The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@’, and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:
getClass().getName() + ‘@’ + Integer.toHexString(hashCode())
toURL
public URL toURL()
throws MalformedURLExceptionConverts this file to a URL.
Throws
toURI
public URI toURI()
throws URISyntaxExceptionConverts this file to a URI.