public class FileOutputStream extends OutputStream
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.
BufferedOutputStream,
FileInputStream| Constructor and Description |
|---|
FileOutputStream(File file)
Constructs a new
FileOutputStream that writes to file. |
FileOutputStream(File file,
boolean append)
Constructs a new
FileOutputStream that writes to file. |
FileOutputStream(FileDescriptor fd)
Constructs a new
FileOutputStream that writes to fd. |
FileOutputStream(String path)
Constructs a new
FileOutputStream that writes to path. |
FileOutputStream(String path,
boolean append)
Constructs a new
FileOutputStream that writes to path. |
| Modifier and Type | Method and Description |
|---|---|
void |
close()
Closes this output stream and releases any system resources
associated with this stream.
|
protected void |
finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
|
FileChannel |
getChannel()
Returns a write-only
FileChannel that shares its position with
this stream. |
FileDescriptor |
getFD()
Returns the underlying file descriptor.
|
void |
write(byte[] buffer,
int byteOffset,
int byteCount)
Writes
len bytes from the specified byte array
starting at offset off to this output stream. |
void |
write(int oneByte)
Writes the specified byte to this output stream.
|
flush, nullOutputStream, writepublic FileOutputStream(File file) throws FileNotFoundException
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.public FileOutputStream(File file, boolean append) throws FileNotFoundException
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.public FileOutputStream(FileDescriptor fd)
FileOutputStream that writes to fd.NullPointerException - if fd is null.public FileOutputStream(String path) throws FileNotFoundException
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.public FileOutputStream(String path, boolean append) throws FileNotFoundException
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.public void close()
throws IOException
OutputStreamclose
is that it closes the output stream. A closed stream cannot perform
output operations and cannot be reopened.
The close method of OutputStream does nothing.
close in interface Closeableclose in interface AutoCloseableclose in class OutputStreamIOException - if an I/O error occurs.protected void finalize()
throws IOException
ObjectNote 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.
finalize in class ObjectIOExceptionpublic FileChannel getChannel()
FileChannel that shares its position with
this stream.public final FileDescriptor getFD() throws IOException
IOExceptionpublic void write(byte[] buffer,
int byteOffset,
int byteCount)
throws IOException
OutputStreamlen bytes from the specified byte array
starting at offset off to this output stream.
The general contract for write(b, off, len) is that
some of the bytes in the array b are written to the
output stream in order; element b[off] is the first
byte written and b[off+len-1] is the last byte written
by this operation.
The write method of OutputStream calls
the write method of one argument on each of the bytes to be
written out. Subclasses are encouraged to override this method and
provide a more efficient implementation.
If b is null, a
NullPointerException is thrown.
If off is negative, or len is negative, or
off+len is greater than the length of the array
b, then an IndexOutOfBoundsException is thrown.
write in class OutputStreambuffer - the data.byteOffset - the start offset in the data.byteCount - the number of bytes to write.IOException - if an I/O error occurs. In particular,
an IOException is thrown if the output
stream is closed.public void write(int oneByte)
throws IOException
OutputStreamwrite is that one byte is written
to the output stream. The byte to be written is the eight
low-order bits of the argument b. The 24
high-order bits of b are ignored.
Subclasses of OutputStream must provide an
implementation for this method.
write in class OutputStreamoneByte - the byte.IOException - if an I/O error occurs. In particular,
an IOException may be thrown if the
output stream has been closed.