java.lang.Object | ||
↳ | java.io.OutputStream | |
↳ | java.io.FileOutputStream |
Known Direct Subclasses |
Known Indirect Subclasses |
An output stream that writes bytes to a file. If the output file exists, it can be replaced or appended to. If it does not exist, a new file will be created.
File file = ...
OutputStream out = null;
try {
out = new BufferedOutputStream(new FileOutputStream(file));
...
finally {
if (out != null) {
out.close();
}
}
}
This stream is not buffered. Most callers should wrap
this stream with a BufferedOutputStream
.
Use FileWriter
to write characters, as opposed to bytes, to a file.
Public Constructors | |||||||||||
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Constructs a new
FileOutputStream that writes to file . | |||||||||||
Constructs a new
FileOutputStream that writes to file . | |||||||||||
Constructs a new
FileOutputStream that writes to fd . | |||||||||||
Constructs a new
FileOutputStream that writes to path . | |||||||||||
Constructs a new
FileOutputStream that writes to path . |
Public Methods | |||||||||||
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Closes this stream.
| |||||||||||
Returns a write-only
FileChannel that shares its position with
this stream. | |||||||||||
Returns the underlying file descriptor.
| |||||||||||
Writes
count bytes from the byte array buffer starting at
position offset to this stream. | |||||||||||
Writes a single byte to this stream.
|
Protected Methods | |||||||||||
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Invoked when the garbage collector has detected that this instance is no longer reachable.
|
[Expand]
Inherited Methods | |||||||||||
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From class
java.io.OutputStream
| |||||||||||
From class
java.lang.Object
| |||||||||||
From interface
java.io.Closeable
| |||||||||||
From interface
java.io.Flushable
| |||||||||||
From interface
java.lang.AutoCloseable
|
Constructs a new FileOutputStream
that writes to file
. The file will be
truncated if it exists, and created if it doesn't exist.
FileNotFoundException | if file cannot be opened for writing. |
---|
Constructs a new FileOutputStream
that writes to file
.
If append
is true and the file already exists, it will be appended to; otherwise
it will be truncated. The file will be created if it does not exist.
FileNotFoundException | if the file cannot be opened for writing. |
---|
Constructs a new FileOutputStream
that writes to fd
.
NullPointerException | if fd is null.
|
---|
Constructs a new FileOutputStream
that writes to path
. The file will be
truncated if it exists, and created if it doesn't exist.
FileNotFoundException | if file cannot be opened for writing. |
---|
Constructs a new FileOutputStream
that writes to path
.
If append
is true and the file already exists, it will be appended to; otherwise
it will be truncated. The file will be created if it does not exist.
FileNotFoundException | if the file cannot be opened for writing. |
---|
Closes this stream. Implementations of this method should free any resources used by the stream. This implementation does nothing.
IOException |
---|
Returns a write-only FileChannel
that shares its position with
this stream.
Returns the underlying file descriptor.
IOException |
---|
Writes count
bytes from the byte array buffer
starting at
position offset
to this stream.
buffer | the buffer to be written. |
---|---|
byteOffset | the start position in buffer from where to get bytes. |
byteCount | the number of bytes from buffer to write to this
stream. |
IOException |
---|
Writes a single byte to this stream. Only the least significant byte of
the integer oneByte
is written to the stream.
oneByte | the byte to be written. |
---|
IOException |
---|
Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.
Note that objects that override finalize
are significantly more expensive than
objects that don't. Finalizers may be run a long time after the object is no longer
reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup.
Note also that finalizers are run on a single VM-wide finalizer thread,
so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary
for a class that has a native peer and needs to call a native method to destroy that peer.
Even then, it's better to provide an explicit close
method (and implement
Closeable
), and insist that callers manually dispose of instances. This
works well for something like files, but less well for something like a BigInteger
where typical calling code would have to deal with lots of temporaries. Unfortunately,
code that creates lots of temporaries is the worst kind of code from the point of view of
the single finalizer thread.
If you must use finalizers, consider at least providing your own
ReferenceQueue
and having your own thread process that queue.
Unlike constructors, finalizers are not automatically chained. You are responsible for
calling super.finalize()
yourself.
Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.
IOException |
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