Java Reference
In-Depth Information
Section 19.6
*19.5
(
Store objects and arrays in a file
) Write a program that stores an array of the
five
int
values
1
,
2
,
3
,
4
and
5
, a
Date
object for the current time, and the
double
value
5.5
into the file named
Exercise19_05.dat
.
*19.6
(
Store
Loan
objects
) The
Loan
class in Listing 10.2 does not implement
Serializable
. Rewrite the
Loan
class to implement
Serializable
. Write
a program that creates five
Loan
objects and stores them in a file named
Exercise19_06.dat
.
*19.7
(
Restore objects from a file
) Suppose a file named
Exercise19_07.dat
has
been created using the
ObjectOutputStream
. The file contains
Loan
objects. The
Loan
class in Listing 10.2 does not implement
Serializable
.
Rewrite the
Loan
class to implement
Serializable
. Write a program that
reads the
Loan
objects from the file and computes the total loan amount.
Suppose you don't know how many
Loan
objects are in the file. Use
EOFException
to end the loop.
Section 19.7
*19.8
(
Update count
) Suppose you want to track how many times a program has
been executed. You can store an
int
to count the file. Increase the count by
1
each time this program is executed. Let the program be
Exercise19_08
and
store the count in
Exercise19_08.dat
.
***19.9
(
Address book
) Supplement VI.B has a case study of using random-access
files for creating and manipulating an address book. Modify the case study by
adding an
Update
button, as shown in Figure 19.19, to enable the user to mod-
ify the address that is being displayed.
F
IGURE
19.19
The application can store, retrieve, and update addresses from a file.
Comprehensive
*19.10
(
Split files
) Suppose you want to back up a huge file (e.g., a 10-GB AVI file) to
a CD-R. You can achieve it by splitting the file into smaller pieces and backing
up these pieces separately. Write a utility program that splits a large file into
smaller ones using the following command:
VideoNote
Split a large file
java Exercise19_10 SourceFile numberOfPieces
The command creates the files
SourceFile.1
,
SourceFile.2
, . . . ,
SourceFile.n
,
where
n
is
numberOfPieces
and the output files are about the same size.
**19.11
(
Split files GUI
) Rewrite Exercise 19.10 with a GUI, as shown in Figure 19.20a.
*19.12
(
Combine files
) Write a utility program that combines the files together into a
new file using the following command:
java Exercise19_12 SourceFile1 . . . SourceFilen TargetFile
The command combines SourceFile1, . . . , and SourceFilen
into
TargetFile.
