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Java™ Platform Standard Ed. 6 |
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java.lang.Object java.io.OutputStream java.io.FileOutputStream
public class FileOutputStream
A file output stream is an output stream for writing data to a
File
or to a FileDescriptor
. Whether or not
a file is available or may be created depends upon the underlying
platform. Some platforms, in particular, allow a file to be opened
for writing by only one FileOutputStream (or other
file-writing object) at a time. In such situations the constructors in
this class will fail if the file involved is already open.
FileOutputStream
is meant for writing streams of raw bytes
such as image data. For writing streams of characters, consider using
FileWriter
.
File
,
FileDescriptor
,
FileInputStream
Constructor Summary | |
---|---|
FileOutputStream(File file)
Creates a file output stream to write to the file represented by the specified File object. |
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FileOutputStream(File file,
boolean append)
Creates a file output stream to write to the file represented by the specified File object. |
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FileOutputStream(FileDescriptor fdObj)
Creates an output file stream to write to the specified file descriptor, which represents an existing connection to an actual file in the file system. |
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FileOutputStream(String name)
Creates an output file stream to write to the file with the specified name. |
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FileOutputStream(String name,
boolean append)
Creates an output file stream to write to the file with the specified name . |
Method Summary | |
---|---|
void |
close()
Closes this file output stream and releases any system resources associated with this stream. |
protected void |
finalize()
Cleans up the connection to the file, and ensures that the close method of this file output stream is
called when there are no more references to this stream. |
FileChannel |
getChannel()
Returns the unique FileChannel
object associated with this file output stream. |
FileDescriptor |
getFD()
Returns the file descriptor associated with this stream. |
void |
write(byte[] b)
Writes b.length bytes from the specified byte array
to this file output stream. |
void |
write(byte[] b,
int off,
int len)
Writes len bytes from the specified byte array
starting at offset off to this file output stream. |
void |
write(int b)
Writes the specified byte to this file output stream. |
Methods inherited from class java.io.OutputStream |
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flush |
Methods inherited from class java.lang.Object |
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clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public FileOutputStream(String name) throws FileNotFoundException
FileDescriptor
object is
created to represent this file connection.
First, if there is a security manager, its checkWrite
method is called with name
as its argument.
If the file exists but is a directory rather than a regular file, does
not exist but cannot be created, or cannot be opened for any other
reason then a FileNotFoundException
is thrown.
name
- the system-dependent filename
FileNotFoundException
- if the file exists but is a directory
rather than a regular file, does not exist but cannot
be created, or cannot be opened for any other reason
SecurityException
- if a security manager exists and its
checkWrite
method denies write access
to the file.SecurityManager.checkWrite(java.lang.String)
public FileOutputStream(String name, boolean append) throws FileNotFoundException
name
. If the second argument is true
, then
bytes will be written to the end of the file rather than the beginning.
A new FileDescriptor
object is created to represent this
file connection.
First, if there is a security manager, its checkWrite
method is called with name
as its argument.
If the file exists but is a directory rather than a regular file, does
not exist but cannot be created, or cannot be opened for any other
reason then a FileNotFoundException
is thrown.
name
- the system-dependent file nameappend
- if true
, then bytes will be written
to the end of the file rather than the beginning
FileNotFoundException
- if the file exists but is a directory
rather than a regular file, does not exist but cannot
be created, or cannot be opened for any other reason.
SecurityException
- if a security manager exists and its
checkWrite
method denies write access
to the file.SecurityManager.checkWrite(java.lang.String)
public FileOutputStream(File file) throws FileNotFoundException
File
object. A new
FileDescriptor
object is created to represent this
file connection.
First, if there is a security manager, its checkWrite
method is called with the path represented by the file
argument as its argument.
If the file exists but is a directory rather than a regular file, does
not exist but cannot be created, or cannot be opened for any other
reason then a FileNotFoundException
is thrown.
file
- the file to be opened for writing.
FileNotFoundException
- if the file exists but is a directory
rather than a regular file, does not exist but cannot
be created, or cannot be opened for any other reason
SecurityException
- if a security manager exists and its
checkWrite
method denies write access
to the file.File.getPath()
,
SecurityException
,
SecurityManager.checkWrite(java.lang.String)
public FileOutputStream(File file, boolean append) throws FileNotFoundException
File
object. If the second argument is
true
, then bytes will be written to the end of the file
rather than the beginning. A new FileDescriptor
object is
created to represent this file connection.
First, if there is a security manager, its checkWrite
method is called with the path represented by the file
argument as its argument.
If the file exists but is a directory rather than a regular file, does
not exist but cannot be created, or cannot be opened for any other
reason then a FileNotFoundException
is thrown.
file
- the file to be opened for writing.append
- if true
, then bytes will be written
to the end of the file rather than the beginning
FileNotFoundException
- if the file exists but is a directory
rather than a regular file, does not exist but cannot
be created, or cannot be opened for any other reason
SecurityException
- if a security manager exists and its
checkWrite
method denies write access
to the file.File.getPath()
,
SecurityException
,
SecurityManager.checkWrite(java.lang.String)
public FileOutputStream(FileDescriptor fdObj)
First, if there is a security manager, its checkWrite
method is called with the file descriptor fdObj
argument as its argument.
fdObj
- the file descriptor to be opened for writing
SecurityException
- if a security manager exists and its
checkWrite
method denies
write access to the file descriptorSecurityManager.checkWrite(java.io.FileDescriptor)
Method Detail |
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public void write(int b) throws IOException
write
method of OutputStream
.
write
in class OutputStream
b
- the byte to be written.
IOException
- if an I/O error occurs.public void write(byte[] b) throws IOException
b.length
bytes from the specified byte array
to this file output stream.
write
in class OutputStream
b
- the data.
IOException
- if an I/O error occurs.OutputStream.write(byte[], int, int)
public void write(byte[] b, int off, int len) throws IOException
len
bytes from the specified byte array
starting at offset off
to this file output stream.
write
in class OutputStream
b
- the data.off
- the start offset in the data.len
- the number of bytes to write.
IOException
- if an I/O error occurs.public void close() throws IOException
If this stream has an associated channel then the channel is closed as well.
close
in interface Closeable
close
in class OutputStream
IOException
- if an I/O error occurs.public final FileDescriptor getFD() throws IOException
FileDescriptor
object that represents
the connection to the file in the file system being used
by this FileOutputStream
object.
IOException
- if an I/O error occurs.FileDescriptor
public FileChannel getChannel()
FileChannel
object associated with this file output stream.
The initial position
of the returned channel will be equal to the
number of bytes written to the file so far unless this stream is in
append mode, in which case it will be equal to the size of the file.
Writing bytes to this stream will increment the channel's position
accordingly. Changing the channel's position, either explicitly or by
writing, will change this stream's file position.
protected void finalize() throws IOException
close
method of this file output stream is
called when there are no more references to this stream.
finalize
in class Object
IOException
- if an I/O error occurs.FileInputStream.close()
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Java™ Platform Standard Ed. 6 |
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