Managing Input/Output Files in Java
The FileOutputStream class
|• Is part of the java.io package|
|• Is an extension of the OutputStream class, an abstract class that describes the behavior of an output stream|
|• Is a low-level class that can be used to send individual, 8-bit bytes to a stream|
|• Has several constructors. The most frequently used constructs a FileOutputStream object from a File object that encapsulates the file's pathname. For example, if fd is the reference of a File object|
|FileOutputStream out = new FileOutputStream(fd);|
|It will construct a FileOutputStream object for sending bytes to the file. If the file already exists, its contents will be replaced (there is an overloaded constructor to specify appending). Because a checked, IOException may occur, the statement should be enclosed in a try block with an appropriate catch.|
|• Has a few useful methods. The two most used are:|
|Because a checked, IOException may occur, calls to these methods should be enclosed in a try block with an appropriate catch. Consult the Java API documentation for more details.|
|• Example. The following program can be used to create a file of numbers on disk.|
|// Open an output stream for the file.|
|out = new FileOutputStream(fd);|
|// This loop asks the user to enter a import|
public class AppFOS
public static void main(String args)
// Local variables and object references.
char again = 'y';
// Get the path name from the user.
System.out.print("Enter the file's complete path name: ");
fd = new File(Keyboard.readString());
// Try to write data to the output stream.
//number and writes it to the
// stream. The user is then asked if they want to enter another.
while (again == 'Y' || again == 'y')
System.out.print("Enter a number: ");
int theNumber = Keyboard.readInt();
System.out.print("Again? (Y/N): ");
again = Keyboard.readChar();
// Close the stream.
System.out.println("Closed - " + fd.getPath());
// Catch an IOException if one is thrown.
catch (IOException e)