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Class java.io.FileInputStream
java.lang.Object
|
+----java.io.InputStream
|
+----java.io.FileInputStream
public class FileInputStream
extends InputStream
A file input stream is an input stream for reading data from a
File
or from a FileDescriptor
.
See Also:
File , FileDescriptor , FileOutputStream
FileInputStream (File)
Creates an input file stream to read from the specified
File
object.
FileInputStream (FileDescriptor)
Creates an input file stream to read from the specified file descriptor.
FileInputStream (String)
Creates an input file stream to read from a file with the
specified name.
available ()
Returns the number of bytes that can be read from this file input
stream without blocking.
close ()
Closes this file input stream and releases any system resources
associated with the stream.
finalize ()
Ensures that the close
method of this file input stream is
called when there are no more references to it.
getFD ()
Returns the opaque file descriptor object associated with this stream.
read ()
Reads a byte of data from this input stream.
read (byte[])
Reads up to b.length
bytes of data from this input
stream into an array of bytes.
read (byte[], int, int)
Reads up to len
bytes of data from this input stream
into an array of bytes.
skip (long)
Skips over and discards n
bytes of data from the
input stream.
FileInputStream
public FileInputStream(String name) throws FileNotFoundException
Creates an input file stream to read from a file with the
specified name.
Parameters:
name - the system-dependent file name.
Throws: FileNotFoundException
if the file is not found.
Throws: SecurityException
if a security manager exists, its
checkRead
method is called with the name
argument to see if the application is allowed read access
to the file.
See Also:
checkRead
FileInputStream
public FileInputStream(File file) throws FileNotFoundException
Creates an input file stream to read from the specified
File
object.
Parameters:
file - the file to be opened for reading.
Throws: FileNotFoundException
if the file is not found.
Throws: SecurityException
if a security manager exists, its
checkRead
method is called with the pathname
of this File
argument to see if the
application is allowed read access to the file.
See Also:
getPath , checkRead
FileInputStream
public FileInputStream(FileDescriptor fdObj)
Creates an input file stream to read from the specified file descriptor.
Parameters:
fdObj - the file descriptor to be opened for reading.
Throws: SecurityException
if a security manager exists, its
checkRead
method is called with the file
descriptor to see if the application is allowed to read
from the specified file descriptor.
See Also:
checkRead
read
public native int read() throws IOException
Reads a byte of data from this input stream. This method blocks
if no input is yet available.
Returns:
the next byte of data, or -1
if the end of the
file is reached.
Throws: IOException
if an I/O error occurs.
Overrides:
read in class InputStream
read
public int read(byte b[]) throws IOException
Reads up to b.length
bytes of data from this input
stream into an array of bytes. This method blocks until some input
is available.
Parameters:
b - the buffer into which the data is read.
Returns:
the total number of bytes read into the buffer, or
-1
if there is no more data because the end of
the file has been reached.
Throws: IOException
if an I/O error occurs.
Overrides:
read in class InputStream
read
public int read(byte b[],
int off,
int len) throws IOException
Reads up to len
bytes of data from this input stream
into an array of bytes. This method blocks until some input is
available.
Parameters:
b - the buffer into which the data is read.
off - the start offset of the data.
len - the maximum number of bytes read.
Returns:
the total number of bytes read into the buffer, or
-1
if there is no more data because the end of
the file has been reached.
Throws: IOException
if an I/O error occurs.
Overrides:
read in class InputStream
skip
public native long skip(long n) throws IOException
Skips over and discards n
bytes of data from the
input stream. The skip
method may, for a variety of
reasons, end up skipping over some smaller number of bytes,
possibly 0
. The actual number of bytes skipped is returned.
Parameters:
n - the number of bytes to be skipped.
Returns:
the actual number of bytes skipped.
Throws: IOException
if an I/O error occurs.
Overrides:
skip in class InputStream
available
public native int available() throws IOException
Returns the number of bytes that can be read from this file input
stream without blocking.
Returns:
the number of bytes that can be read from this file input
stream without blocking.
Throws: IOException
if an I/O error occurs.
Overrides:
available in class InputStream
close
public native void close() throws IOException
Closes this file input stream and releases any system resources
associated with the stream.
Throws: IOException
if an I/O error occurs.
Overrides:
close in class InputStream
getFD
public final FileDescriptor getFD() throws IOException
Returns the opaque file descriptor object associated with this stream.
Returns:
the file descriptor object associated with this stream.
Throws: IOException
if an I/O error occurs.
See Also:
FileDescriptor
finalize
protected void finalize() throws IOException
Ensures that the close
method of this file input stream is
called when there are no more references to it.
Throws: IOException
if an I/O error occurs.
Overrides:
finalize in class Object
See Also:
close
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