Summary: Ctors | Methods | Protected Methods | Inherited Methods | [Expand All]

public class

FileInputStream

java.lang.Object
↳	java.io.InputStream
	↳	java.io.FileInputStream

Known Direct Subclasses

ParcelFileDescriptor.AutoCloseInputStream

Known Indirect Subclasses

AssetFileDescriptor.AutoCloseInputStream

Class Overview

An input stream that reads bytes from a file.

        
         File file = ...
   InputStream in = null;
   try {
     in = new BufferedInputStream(new FileInputStream(file));
     ...
        
        finally {
     if (in != null) {
       in.close();
     }
   }
 }

This stream is not buffered . Most callers should wrap this stream with a BufferedInputStream .

Use FileReader to read characters, as opposed to bytes, from a file.

Summary

Public Constructors
	FileInputStream ( File file) Constructs a new `FileInputStream` that reads from `file` .
	FileInputStream ( FileDescriptor fd) Constructs a new `FileInputStream` that reads from `fd` .
	FileInputStream ( String path) Equivalent to `new FileInputStream(new File(path))` .

Public Methods
int	available () Returns an estimated number of bytes that can be read or skipped without blocking for more input.
void	close () Closes this stream.
FileChannel	getChannel () Returns a read-only `FileChannel` that shares its position with this stream.
final FileDescriptor	getFD () Returns the underlying file descriptor.
int	read () Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
int	read (byte[] buffer, int byteOffset, int byteCount) Reads up to `byteCount` bytes from this stream and stores them in the byte array `buffer` starting at `byteOffset` .
long	skip (long byteCount) Skips at most `byteCount` bytes in this stream.

Protected Methods
void	finalize () Ensures that all resources for this stream are released when it is about to be garbage collected.

[Expand]

Inherited Methods

From class java.io.InputStream

int	available () Returns an estimated number of bytes that can be read or skipped without blocking for more input.
void	close () Closes this stream.
void	mark (int readlimit) Sets a mark position in this InputStream.
boolean	markSupported () Indicates whether this stream supports the `mark()` and `reset()` methods.
int	read (byte[] buffer) Equivalent to `read(buffer, 0, buffer.length)` .
abstract int	read () Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
int	read (byte[] buffer, int byteOffset, int byteCount) Reads up to `byteCount` bytes from this stream and stores them in the byte array `buffer` starting at `byteOffset` .
synchronized void	reset () Resets this stream to the last marked location.
long	skip (long byteCount) Skips at most `byteCount` bytes in this stream.

From class java.lang.Object

Object	clone () Creates and returns a copy of this `Object` .
boolean	equals ( Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize () Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class <?>	getClass () Returns the unique instance of `Class` that represents this object's class.
int	hashCode () Returns an integer hash code for this object.
final void	notify () Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll () Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString () Returns a string containing a concise, human-readable description of this object.
final void	wait () Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait (long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait (long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

From interface java.io.Closeable

From interface java.lang.AutoCloseable

Public Constructors

public FileInputStream ( File file)

Added in API level 1

Constructs a new FileInputStream that reads from file .

Parameters

file	the file from which this stream reads.

Throws

FileNotFoundException	if `file` does not exist.

public FileInputStream ( FileDescriptor fd)

Added in API level 1

Constructs a new FileInputStream that reads from fd .

Parameters

fd	the FileDescriptor from which this stream reads.

Throws

NullPointerException	if `fd` is `null` .

public FileInputStream ( String path)

Added in API level 1

Equivalent to new FileInputStream(new File(path)) .

Throws

FileNotFoundException

Public Methods

public int available ()

Added in API level 1

Returns an estimated number of bytes that can be read or skipped without blocking for more input.

Note that this method provides such a weak guarantee that it is not very useful in practice.

Firstly, the guarantee is "without blocking for more input" rather than "without blocking": a read may still block waiting for I/O to complete — the guarantee is merely that it won't have to wait indefinitely for data to be written. The result of this method should not be used as a license to do I/O on a thread that shouldn't be blocked.

Secondly, the result is a conservative estimate and may be significantly smaller than the actual number of bytes available. In particular, an implementation that always returns 0 would be correct. In general, callers should only use this method if they'd be satisfied with treating the result as a boolean yes or no answer to the question "is there definitely data ready?".

Thirdly, the fact that a given number of bytes is "available" does not guarantee that a read or skip will actually read or skip that many bytes: they may read or skip fewer.

It is particularly important to realize that you must not use this method to size a container and assume that you can read the entirety of the stream without needing to resize the container. Such callers should probably write everything they read to a ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're reading from a file, length() returns the current length of the file (though assuming the file's length can't change may be incorrect, reading a file is inherently racy).

The default implementation of this method in InputStream always returns 0. Subclasses should override this method if they are able to indicate the number of bytes available.

Returns

the estimated number of bytes available

Throws

IOException

public void close ()

Added in API level 1

Closes this stream. Concrete implementations of this class should free any resources during close. This implementation does nothing.

Throws

IOException

public FileChannel getChannel ()

Added in API level 1

Returns a read-only FileChannel that shares its position with this stream.

public final FileDescriptor getFD ()

Added in API level 1

Returns the underlying file descriptor.

Throws

IOException

public int read ()

Added in API level 1

Reads a single byte from this stream and returns it as an integer in the range from 0 to 255. Returns -1 if the end of the stream has been reached. Blocks until one byte has been read, the end of the source stream is detected or an exception is thrown.

Throws

IOException

public int read (byte[] buffer, int byteOffset, int byteCount)

Added in API level 1

Reads up to byteCount bytes from this stream and stores them in the byte array buffer starting at byteOffset . Returns the number of bytes actually read or -1 if the end of the stream has been reached.

Throws

IOException

public long skip (long byteCount)

Added in API level 1

Skips at most byteCount bytes in this stream. The number of actual bytes skipped may be anywhere between 0 and byteCount . If byteCount is negative, this method does nothing and returns 0, but some subclasses may throw.

Note the "at most" in the description of this method: this method may choose to skip fewer bytes than requested. Callers should always check the return value.

This default implementation reads bytes into a temporary buffer. Concrete subclasses should provide their own implementation.

Returns

the number of bytes actually skipped.

Throws

IOException

Protected Methods

protected void finalize ()

Added in API level 1

Ensures that all resources for this stream are released when it is about to be garbage collected.

Throws

IOException	if an error occurs attempting to finalize this stream.

Results

Interfaces

Classes

Exceptions

Errors

FileInputStream

Class Overview

See Also

Summary

Public Constructors

public FileInputStream ( File file)

Parameters

Throws

public FileInputStream ( FileDescriptor fd)

Parameters

Throws

public FileInputStream ( String path)

Throws

Public Methods

public int available ()

Returns

Throws

public void close ()

Throws

public FileChannel getChannel ()

public final FileDescriptor getFD ()

Throws

public int read ()

Throws

public int read (byte[] buffer, int byteOffset, int byteCount)

Throws

public long skip (long byteCount)

Returns

Throws

Protected Methods

protected void finalize ()

Throws