File, input and output

Computer File

Collection of data stored on nonvolatile devices.

Text File

Contains readable data encoded in ASCII or Unicode.

Binary File

Contains data in binary format, not human-readable.

Root Directory

Main directory of a storage device.

Path

Complete list of directories leading to a file.

Path Identifier

Character separating path components in Windows.

Delimiter

Character separating path components in UNIX.

File Operations

Tasks like opening, reading, and deleting files.

Path Class

Creates objects with file and directory information.

Files Class

Performs operations on files and directories.

java.nio.file

Java package for file and path handling.

FileSystem Class

Instantiates objects representing the file system.

FileSystems Class

Contains factory methods for creating FileSystem objects.

getDefault() Method

Returns the default file system instance.

getPath() Method

Defines a path using the file system.

Escape Sequence

Backslash used to denote special characters in strings.

Hierarchy

Organizational structure of folders within directories.

Folder

Container for organizing files on a storage device.

Creation Date

Timestamp indicating when a file was created.

File Size

Amount of disk space occupied by a file.

File Attributes

Metadata describing properties of a file.

Input Stream

Flow of data read from a file.

Output Stream

Flow of data written to a file.

Path Delimiter

Use double backslashes for a single backslash.

Paths Class

Helper class to create Path objects easily.

get() Method

Calls getPath() without needing FileSystem object.

Path Object

Represents a file path in the application.

Absolute Path

Complete path to locate a file directly.

Relative Path

Path dependent on current directory context.

toAbsolutePath() Method

Converts relative path to absolute path.

PathDemo2 Program

Converts user input filename to absolute path.

toString() Method

Returns String representation of the Path.

getFileName() Method

Returns last element in the Path sequence.

getNameCount() Method

Counts name elements in the Path.

getName(int) Method

Retrieves name at specified index in Path.

Path Indexing

Top-level element is at index 0.

File System

Organizes files and directories on a computer.

Current Directory

Folder where the program is executed.

SampleFile.txt

Example file referenced in path operations.

Path Syntax

C:\Java\Chapter.11\SampleFile.txt is a valid path.

Path Operations

Use Path object to perform file operations.

Java Scanner

Used to read user input in programs.

Path Representation

Path is known as filePath in the application.

Subfolder

Folder contained within another folder.

Path Methods Summary

Useful methods for manipulating Path objects.

Path

Represents a file or directory location.

Paths.get()

Creates a Path object from a string.

getNameCount()

Returns number of elements in the path.

getFileName()

Retrieves the file name from the path.

checkAccess()

Verifies file accessibility permissions.

AccessMode

Constants for file access permissions.

READ

Permission to read the file.

WRITE

Permission to write to the file.

EXECUTE

Permission to execute the file.

Files.exists()

Checks if a file exists at the path.

IOException

Exception thrown for file access issues.

readAttributes()

Retrieves file attributes using a Path.

BasicFileAttributes

Class containing basic file attribute methods.

size()

Returns file size in bytes.

creationTime()

Returns file creation timestamp.

lastModifiedTime()

Returns last modified timestamp of the file.

PathDemo

Example program demonstrating file path operations.

PathDemo3

Checks if a file can be read and executed.

PathDemo4

Demonstrates retrieving file attributes.

getFileSystem()

Retrieves the file system associated with the path.

provider()

Gets the file system provider.

try-catch

Handles exceptions during file access.

System.out.println()

Prints output to the console.

for loop

Iterates over elements in the file path.

Path

Represents file and directory pathnames.

Paths

Utility class for creating Path instances.

BasicFileAttributes

Stores file attributes like creation time.

FileTime

Represents time in yyyy-mm-ddThh:mm:ss format.

InputStream

Abstract class for input operations.

OutputStream

Abstract class for output operations.

FileInputStream

Reads data from disk files.

FileOutputStream

Writes data to disk files.

BufferedInputStream

Buffers input for efficient reading.

BufferedOutputStream

Buffers output for efficient writing.

PrintStream

Handles output to standard output device.

Reader

Abstract class for reading character streams.

BufferedReader

Buffers characters for efficient reading.

BufferedWriter

Buffers characters for efficient writing.

getBytes()

Converts String to byte array.

flush()

Flushes buffered output stream.

close()

Closes the output stream.

write(byte[] b)

Writes byte array to output stream.

write(byte[] b, int off, int len)

Writes specified bytes from array.

IOException

Exception for input/output errors.

System.out

Standard output stream in Java.

try-catch block

Handles exceptions during execution.

println()

Prints output to console with newline.