File I/O - Absolute Java - page 615

Display 10.13 Writing to a Binary File (part 2 of 2)

18 catch (IOException e)
19 {
20 System.out.println("Problem with file output.");
21 }
22 }
23 }

F ILE R EPRESENTATION (after program is run)

0
1
2
3
4

This is a binary file. It really contains representations
of each number as bytes—that is, zeros and ones—and
is read as bytes. You cannot read this file with your
text editor.

Display 10.14 Some Methods in the Class ObjectOutputStream (part 1 of 2)

ObjectOutputStream and FileOutputStream are in the java.io package.
public ObjectOutputStream(OutputStream streamObject)

There is no constructor that takes a file name as an argument. If you want to create a stream using
a file name, use

new ObjectOutputStream( new FileOutputStream( File_Name ))
This creates a blank file. If there already is a file named File_Name , then the old contents of the
file are lost.

If you want to create a stream using an object of the class File , use

new ObjectOutputStream( new FileOutputStream( File_Object ))
The constructor for FileOutputStream may throw a FileNotFoundException , which is a
kind of IOException . If the FileOutputStream constructor succeeds, then the constructor for
ObjectOutputStream may throw a different IOException .
public void writeInt( int n) throws IOException

Writes the int value n to the output stream.

public void writeShort( short n) throws IOException
Writes the short value n to the output stream.
public void writeLong( long n) throws IOException

Writes the long value n to the output stream.
public void writeDouble( double x) throws IOException

Writes the double value x to the output stream.

(continued)