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## java.io
Class FileInputStream

    java.lang.Object
      |
      +--java.io.InputStream
            |
            +--java.io.FileInputStream

public class FileInputStream
extends InputStream

A `FileInputStream` obtains input bytes from a file in a file system. What files are available depends on the host environment.

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

Constructor Summary
`FileInputStream(File file)` Creates a `FileInputStream` by opening a connection to an actual file, the file named by the `File` object `file` in the file system.
`FileInputStream(FileDescriptor fdObj)` Creates a `FileInputStream` by using the file descriptor `fdObj`, which represents an existing connection to an actual file in the file system.
`FileInputStream(String name)` Creates a `FileInputStream` by opening a connection to an actual file, the file named by the path name `name` in the file system.

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.
`protected 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 `FileDescriptor` object that represents the connection to the actual file in the file system being used by this `FileInputStream`.
`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
`mark, markSupported, reset`

Methods inherited from class java.lang.Object
`clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### FileInputStream

    public FileInputStream(String name)
                    throws FileNotFoundException

  Creates a `FileInputStream` by opening a connection to an actual file, the file named by the path name `name` in the file system. A new `FileDescriptor` object is created to represent this file connection.

  First, if there is a security manager, its `checkRead` method is called with the `name` argument as its argument.

  If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a `FileNotFoundException` is thrown.

  Parameters:
    `name` - the system-dependent file name.
  Throws:
    `FileNotFoundException` - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
    `SecurityException` - if a security manager exists and its `checkRead` method denies read access to the file.
  See Also:
    `SecurityManager.checkRead(java.lang.String)`

### FileInputStream

    public FileInputStream(File file)
                    throws FileNotFoundException

  Creates a `FileInputStream` by opening a connection to an actual file, the file named by the `File` object `file` in the file system. A new `FileDescriptor` object is created to represent this file connection.

  First, if there is a security manager, its `checkRead` method is called with the path represented by the `file` argument as its argument.

  If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading then a `FileNotFoundException` is thrown.

  Parameters:
    `file` - the file to be opened for reading.
  Throws:
    `FileNotFoundException` - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
    `SecurityException` - if a security manager exists and its `checkRead` method denies read access to the file.
  See Also:
    `File.getPath()`, `SecurityManager.checkRead(java.lang.String)`

### FileInputStream

    public FileInputStream(FileDescriptor fdObj)

  Creates a `FileInputStream` by using the file descriptor `fdObj`, which represents an existing connection to an actual file in the file system.

  If there is a security manager, its `checkRead` method is called with the file descriptor `fdObj` as its argument to see if it's ok to read the file descriptor. If read access is denied to the file descriptor a `SecurityException` is thrown.

  If `fdObj` is null then a `NullPointerException` is thrown.

  Parameters:
    `fdObj` - the file descriptor to be opened for reading.
  Throws:
    `SecurityException` - if a security manager exists and its `checkRead` method denies read access to the file descriptor.
  See Also:
    `SecurityManager.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.
  Overrides:
    `read` in class `InputStream`
  Returns:
    the next byte of data, or `-1` if the end of the file is reached.
  Throws:
    `IOException` - if an I/O error occurs.

### 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.
  Overrides:
    `read` in class `InputStream`
  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.

### 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.
  Overrides:
    `read` in class `InputStream`
  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.

### 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.
  Overrides:
    `skip` in class `InputStream`
  Parameters:
    `n` - the number of bytes to be skipped.
  Returns:
    the actual number of bytes skipped.
  Throws:
    `IOException` - if an I/O error occurs.

### available

    public int available()
                  throws IOException

  Returns the number of bytes that can be read from this file input stream without blocking.
  Overrides:
    `available` in class `InputStream`
  Returns:
    the number of bytes that can be read from this file input stream without blocking.
  Throws:
    `IOException` - if an I/O error occurs.

### close

    public void close()
               throws IOException

  Closes this file input stream and releases any system resources associated with the stream.
  Overrides:
    `close` in class `InputStream`
  Throws:
    `IOException` - if an I/O error occurs.

### getFD

    public final FileDescriptor getFD()
                               throws IOException

  Returns the `FileDescriptor` object that represents the connection to the actual file in the file system being used by this `FileInputStream`.
  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.
  Overrides:
    `finalize` in class `Object`
  Throws:
    `IOException` - if an I/O error occurs.
  See Also:
    `close()`

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