Java Reference
In-Depth Information
Working with Paths
Typically, a file system stores objects (files, directories, symbolic links, etc.) in a hierarchical fashion. A file system uses
one or more root nodes that serve as the root of the hierarchy. An object in a file system has a path, which is typically
represented as a string, such as
C:\home\test.txt
on Windows, and
/home/test.txt
on UNIX-like operating
systems. A path string may contain multiple components separated by a special character called
separator
or
delimiter
. For example, the path
C:\home\test.txt
consists of three components:
C:\
as the root,
home
as a directory,
and
test.txt
as a file name. A backslash is a path separator on Windows. UNIX-like operating systems use a forward
slash (
/
) as the path separator. Note that path representation is platform-dependent.
A path can be absolute or relative. If a path starts with a root node, it is an absolute path. A relative path does not
start with a root node. No additional information is needed to locate an object referred in a file system by an absolute
path. Additional information is needed to locate an object referred in a file system by a relative path. For example, on
Windows, the path
C:\home\test.txt
is an absolute path because it starts with the root node
C:\
, whereas the path
luci1.txt
is a relative path. To locate the
luci1.txt
file, you need more information, such as the path of the directory
in which it exists.
A
Path
object is a programmatic representation of a path of an object in a file system such as a file, a directory,
and a symbolic link. A file system path is platform-dependent, so is a
Path
object.
Path
is an interface in the
java.nio.file
package. When you work with a
Path
object, it is most likely that you
will also need to work with its two companion classes:
Paths
and
Files
. A path does not have to exist in a file system
to create a
Path
object to represent it in a Java program.
■
as a developer, you will be using
Path
objects most of the time when working with NIO.2 apI. the path apI meets
most of the file I/O-related needs of a developer. It has been designed to work with the old
java.io.File
apI. You can
get a
Path
object from a
File
object using the method
toPath()
of the
File
class. You can get a
File
object from a
Path
object using the
toFile()
method of a
Path
object.
Tip
You can perform two kinds of operations on a
Path
object:
•
Path-related operations
•
The methods in the
Path
interface let you perform path-related operations on a
Path
object that may include
the following:
File I/O operations
•
Accessing the components of a path such as the file name, root name, etc.
.txt
, comparing if
•
Comparing and testing paths. For example, checking if a path ends with
two paths are identical, checking if a path is absolute or relative, etc.
•
The
Path
interface does not include any methods to perform file I/O operations. You need to use the
Files
class
to perform the file I/O operations on a
Path
object. The
Files
class consists of all
static
methods. I will cover using
the
Files
class shortly.
Combining and resolving paths.
