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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.

Since:
JDK1.0
See Also:
File, FileDescriptor, FileOutputStream

Constructor Summary
 FileInputStream(String name)
Creates an input file stream to read from a file with the specified name.
 FileInputStream(File file)
Creates an input file stream to read from the specified File object.
 FileInputStream(FileDescriptor fdObj)
Creates an input file stream to read from the specified file descriptor.
 

Method Summary
int  available()
Returns the number of bytes that can be read from this file input stream without blocking.
void  close()
Closes this file input stream and releases any system resources associated with the stream.
void  finalize()
Ensures that the close method of this file input stream is called when there are no more references to it.
FileDescriptor  getFD()
Returns the opaque file descriptor object associated with this stream.
int  read()
Reads a byte of data from this input stream.
int  read(byte[] b)
Reads up to b.length bytes of data from this input stream into an array of bytes.
int  read(byte[] b, int off, int len)
Reads up to len bytes of data from this input stream into an array of bytes.
long  skip(long n)
Skips over and discards n bytes of data from the input stream.
 
Methods inherited from class java.io.InputStream
 available, close, mark, markSupported, read, read, read, reset, skip
 
Methods inherited from class java.lang.Object
 clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

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.
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(java.lang.String)

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.
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(java.lang.String)

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(java.io.FileDescriptor)
Method Detail

read

public 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 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 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 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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