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Chapter 11 The java.io Package |
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Chapter 11 The java.io Package |
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java.io.FileOutputStream
java.io.OutputStream
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JDK 1.0 or later
The FileOutputStream class represents a byte stream that writes data to a file. The file can be specified using a FileDescriptor, a File object, or a String that represents a pathname. All of the constructors can throw a SecurityException if the application does not have permission to write to the specified file.
FileOutputStream provides a low-level interface for writing data to a file. Wrap a FileOutputStream with a DataOutputStream or a PrintStream if you need a higher-level interface that can handle writing strings and binary data. You should also think about wrapping a FileOutputStream with a BufferedOutputStream to increase writing efficiency.
Data must be written sequentially to a FileOutputStream; you can either overwrite existing data or append data to the end of the file. If you need random access to file data, use the RandomAccessFile class instead.
public class java.io.FileOutputStream extends java.io.OutputStream {
// Constructors
public FileOutputStream(String name);
public FileOutputStream(String name, boolean append); // New in 1.1
public FileOutputStream(File file);
public FileOutputStream(FileDescriptor fdObj);
// Public Instance Methods
public native void close();
public final FileDescriptor getFD();
public native void write(int b);
public void write(byte[] b);
public void write(byte[] b, int off, int len);
// Protected Instance Methods
protected void finalize();
}
A String that contains the pathname of the file to be used for output. The path must conform to the requirements of the native operating system.
If the named file cannot be found.
If the application does not have permission to write to the named file.
This constructor creates a FileOutputStream that sends its output to the file named by the specified String.
public FileOutputStream(String name, boolean append) throws IOException
New as of JDK 1.1
A String that contains the pathname of the file to be used for output. The path must conform to the requirements of the native operating system.
Specifies whether or not data is appended to the output stream.
If the named file cannot be found.
If the application does not have permission to write to the named file.
This constructor creates a FileOutputStream that sends its output to the named file. If append is true, the stream is positioned at the end of the file, and data is appended to the end of the file. Otherwise, if append is false, the stream is positioned at the beginning of the file, and any previous data is overwritten.
The File to use as output.
If the named file cannot be found.
If the application does not have permission to write to the named file.
This constructor creates a FileOutputStream that sends its output to the file represented by the specified File.
The FileDescriptor of the file to use as output.
If the application does not have permission to write to the specified file.
If FileDescriptor is null.
This constructor creates a FileOutputStream that sends its output to the file identified by the given FileDescriptor.
If any kind of I/O error occurs.
OutputStream.close()
This method closes this file output stream and releases any resources used by it.
If there is no FileDescriptor associated with this object.
This method returns the file descriptor associated with the data source of this FileOutputStream.
The value to write to the stream.
If any kind of I/O error occurs.
OutputStream.write(int)
This method writes a byte containing the low-order eight bits of the given value to the output stream.
An array of bytes to write to the stream.
If any kind of I/O error occurs.
OutputStream.write(byte[])
This method writes the entire contents of the given array to the output stream.
An array of bytes to write to the stream.
An offset into the byte array.
The number of bytes to write.
If any kind of I/O error occurs.
OutputStream.write(byte[], int, int)
This method writes len bytes from the given array, starting at element off, to the output stream.
If any kind of I/O error occurs.
This method is called when the FileOutputStream is garbage-collected to ensure that close() is called. If the stream has a valid file descriptor, the close() method is called to free the system resources used by this stream.
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Method |
Inherited From |
Method |
Inherited From |
|---|---|---|---|
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clone() |
Object |
equals(Object) |
Object |
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flush() |
OutputStream |
getClass() |
Object |
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hashCode() |
Object |
notify() |
Object |
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notifyAll() |
Object |
toString() |
Object |
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wait() |
Object |
wait(long) |
Object |
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wait(long, int) |
Object |
BufferedOutputStream, DataOutputStream, File, FileDescriptor, FileNotFoundException, IOException, NullPointerException, OutputStream, PrintStream, RandomAccessFile, SecurityException
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| FileNotFoundException |  |
FileReader |
