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public class

FileInputStream

extends InputStream
implements Closeable
java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.FileInputStream
Known Direct Subclasses

Class Overview

FileInputStream is a class for reading bytes from a file. This class may also be used with other InputStreams, ie: BufferedInputStream, to read data from a file with buffering.

See Also

Summary

Public Constructors
FileInputStream(File file)
Constructs a new FileInputStream on the File file.
FileInputStream(FileDescriptor fd)
Constructs a new FileInputStream on the FileDescriptor fd.
FileInputStream(String fileName)
Constructs a new FileInputStream on the file named fileName.
Public Methods
int available()
Returns a int representing then number of bytes that are available before this InputStream will block.
void close()
Close the FileInputStream.
FileChannel getChannel()
Returns the FileChannel equivalent to this input stream.
final FileDescriptor getFD()
Returns the FileDescriptor representing the operating system resource for this FileInputStream.
int read(byte[] buffer, int offset, int count)
Reads at most count bytes from the FileInputStream and stores them in byte array buffer starting at offset.
int read(byte[] buffer)
Reads bytes from the FileInputStream and stores them in byte array buffer.
int read()
Reads a single byte from this FileInputStream and returns the result as an int.
long skip(long count)
Skips count number of bytes in this FileInputStream.
Protected Methods
void finalize()
This method ensures that all resources for this file are released when it is about to be garbage collected.
[Expand]
Inherited Methods
From class java.io.InputStream
From class java.lang.Object
From interface java.io.Closeable

Public Constructors

public FileInputStream (File file)

Constructs a new FileInputStream on the File file. If the file does not exist, the FileNotFoundException is thrown.

Parameters
file the File on which to stream reads.
Throws
FileNotFoundException If the file is not found.
See Also

public FileInputStream (FileDescriptor fd)

Constructs a new FileInputStream on the FileDescriptor fd. The file must already be open, therefore no FileNotFoundException will be thrown.

Parameters
fd the FileDescriptor on which to stream reads.
See Also

public FileInputStream (String fileName)

Constructs a new FileInputStream on the file named fileName. If the file does not exist, the FileNotFoundException is thrown. The fileName may be absolute or relative to the System property "user.dir".

Parameters
fileName the file on which to stream reads.
Throws
FileNotFoundException If the fileName is not found.

Public Methods

public int available ()

Returns a int representing then number of bytes that are available before this InputStream will block. This method always returns the size of the file minus the current position.

Returns
  • the number of bytes available before blocking.
Throws
IOException If an error occurs in this stream.

public void close ()

Close the FileInputStream.

Throws
IOException If an error occurs attempting to close this FileInputStream.

public FileChannel getChannel ()

Returns the FileChannel equivalent to this input stream.

The file channel is read-only and has an initial position within the file that is the same as the current position of the FileInputStream within the file. All changes made to the underlying file descriptor state via the channel are visible by the input stream and vice versa.

Returns
  • the file channel representation for this FileInputStream.

public final FileDescriptor getFD ()

Returns the FileDescriptor representing the operating system resource for this FileInputStream.

Returns
  • the FileDescriptor for this FileInputStream.
Throws
IOException If an error occurs attempting to get the FileDescriptor of this FileInputStream.

public int read (byte[] buffer, int offset, int count)

Reads at most count bytes from the FileInputStream and stores them in byte array buffer starting at offset. Answer the number of bytes actually read or -1 if no bytes were read and end of stream was encountered.

Parameters
buffer the byte array in which to store the read bytes.
offset the offset in buffer to store the read bytes.
count the maximum number of bytes to store in buffer.
Returns
  • the number of bytes actually read or -1 if end of stream.
Throws
IOException If the stream is already closed or another IOException occurs.

public int read (byte[] buffer)

Reads bytes from the FileInputStream and stores them in byte array buffer. Answer the number of bytes actually read or -1 if no bytes were read and end of stream was encountered.

Parameters
buffer the byte array in which to store the read bytes.
Returns
  • the number of bytes actually read or -1 if end of stream.
Throws
IOException If the stream is already closed or another IOException occurs.

public int read ()

Reads a single byte from this FileInputStream and returns the result as an int. The low-order byte is returned or -1 of the end of stream was encountered.

Returns
  • the byte read or -1 if end of stream.
Throws
IOException If the stream is already closed or another IOException occurs.

public long skip (long count)

Skips count number of bytes in this FileInputStream. Subsequent read()'s will not return these bytes unless reset() is used. This method may perform multiple reads to read count bytes.

Parameters
count the number of bytes to skip.
Returns
  • the number of bytes actually skipped.
Throws
IOException If the stream is already closed or another IOException occurs.

Protected Methods

protected void finalize ()

This method ensures that all resources for this file are released when it is about to be garbage collected.

Throws
IOException If an error occurs attempting to finalize this FileInputStream.