330 Java Tips.pdf - FTP Server

General Java Questions I
I could not quite get it using the ZipOutputStream because it simply creates a new file
and write only that entry for me. The rest of the original entries are gone.
Does anyone have a solution for this?
Answer:
1) Read the file (myfile.properties) out of the original Zip Archive (original.zip)
2) Make your changes, write the file to the file system
3) Create a New Archive (originalNew.zip)
4) Write your edited file (myfile.properties) to originalNew.zip
5) loop through all the entries in the original Zip archive (original.zip), adding them to
the new archive (originalNew.zip) EXCEPT for the file you are replacing
(myfile.properties)
6) When you're done, erase the original and rename your new one to original.zip.
I believe that this may be the only way to do this, since there doesn't seem to be any
random access in the ZIP file.
--
Kevin T. Smith
Q: About the order of my elements in hastable...
I save some data into hashtable.
For example,
hashtable.put ( "1", "one" );
hashtable.put ( "2", "two" );
hashtable.put ("3" , "three" );
when I get back the element from hashtable using Enumeration class ,
Enumeraton e = hashtable.keys();
while ( e.hasMoreElements() ){
Object k = e.nextElement();
Object v = hashtable.get (k );
}
the default result is
"3","three"
"2", "two"
"1", "one"
here I want to get the data sorted as ascending. ( the order as I insert ) such as
"1", "one"
"2", "two"
"3", "three"
or is it possible to get the data from end of hashtable?
Answer: When you insert elements into a Hashtable, they will not be stored in the
order you insert them. They are stored in a way that makes it easy to find them by the
key you specify.
So, you must either use another data structure (e.g. Vector) or sort them after you
retrieve them from the Hashtable (e.g. by using java.util.Collections, java.util.Arrays).
--
Marco Schmidt
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