Can java.util.Properties store binary data

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Rebus77 - 16 Nov 2006 21:29 GMT

Guys,

I am trying to write a class similar to java.lang.Properties, except
that the entries should be in order (alphabetically), and it should
also be able to store binary data(ie public key and digital signature).

... but I do not want to reinvert the wheel. Is there such a class in
the JDK? or something similar?

I am trying to use SortedMap, and write out the entries one by one in a
file, using Base64 to encode the binary data... but that puts '='s in
... I am having some trouble reading the binary data back.

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Timothy Bendfelt - 16 Nov 2006 21:43 GMT

If you write the file using the store() method on properties the necessary
escaping will be applied to characters within the value such that it can
be parsed by the load() method. That way you can use whatever string
encoding you want (i.e. base64) for your binary serialization.

> Guys,
>
[quoted text clipped - 8 lines]
> file, using Base64 to encode the binary data... but that puts '='s in
> ... I am having some trouble reading the binary data back.

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Thomas Weidenfeller - 17 Nov 2006 08:09 GMT

> I am trying to write a class similar to java.lang.Properties, except
> that the entries should be in order (alphabetically), and it should
> also be able to store binary data(ie public key and digital signature).

Java comes with a key store for digital signatures. Maybe that would
work better for you.

/Thomas

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Dale King - 28 Nov 2006 12:58 GMT

> Guys,
>
> I am trying to write a class similar to java.lang.Properties, except
> that the entries should be in order (alphabetically),

java.util.Properties is an example of why one should follow the design
principle of favoring composition over inheritance. Properties is a
subclass of Hashtable. That means it will always be backed by a
Hashtable. Instead they should have used composition and Properties
should have contained an instace of a Map and you would be able to
choose the Map implementation.

> and it should
> also be able to store binary data(ie public key and digital signature).

> file, using Base64 to encode the binary data... but that puts '='s in
> .... I am having some trouble reading the binary data back.

Properties only does text data. You have to convert it to text as you
suggested.

The = should be insignificant after the initial separator between the
key and value. Are you sure that the problem is not that the base64 is
broken over more than one line and you are not escaping the newline?

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Dale King

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Can java.util.Properties store binary data

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