Java Reference
In-Depth Information
Display 10.13
Writing to a Binary File
(part 2 of 2)
8
try
9
{
10
ObjectOutputStream outputStream =
11
new
ObjectOutputStream(
new
FileOutputStream("numbers.dat"));
12
int
i;
13
for
(i = 0; i < 5; i++)
14
outputStream.writeInt(i);
15
System.out.println("Numbers written to the file numbers.dat.");
16
outputStream.close();
17
}
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, you 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
, you 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
.