Re: Unescaping Unicode code points in a Java string
David Lee Lambert wrote:
On Fri, 01 Sep 2006 01:09:40 -0400, Dale King wrote:
"Greg" <greghe@pacbell.net> wrote in message
news:1157007079.550984.122030@m79g2000cwm.googlegroups.com...
My Java program reads in (from an external source) text that contains
the same sort of unicode character escape sequences as java source
code. For example, one such string might be:
"En Espa\u00f1ol"
Naturally, I would like to convert the five characters subsequence,
"\u00f1", into the single character codepoint (hex 00F1) that those
characters actually represent:
"En Espa?ol"
It's a bit more complicated than that because you will also need to
support things like \\ to actually insert a backslash and perhaps
support things like \n.
If he is defining a new specification for escaped input, this would be
nice but not necessary. "\" can be escaped as "\u005C", and a newline
as "\u000A". In Java source code, "\u005C" results in a malformed string
literal (which means one needs to use "\n" instead), but that escape
sequence is permitted in properties files.
It's up to him what he wants to specify, but personally I would prefer
the \\ and \n.
On the other hand, the Java
compiler and Properties.load() do not recognize the C escape-sequences
"\v" and "\a" for VT and BEL.
Which is understandable. BEL is specific to consoles and Java has no
real support for consoles because they are too platform specific and VT
is rarely used.
I think Arne's response (that used a regular expression) was too
complicated, and the response to which you are responding was
poorly-thought-out (because strings are immutable in Java). Here's a
possible solution:
String unescape(String s) {
The proper time to do the conversion is when the text is being read from
the "external source" using some form of FilterReader subclass. I
remember now that I wrote one of those once, but after a long search I
have figured out that I left that code at my previous employer and did
not keep a copy of it (which is a shame because that was part of
something that was some really good work).
--
Dale King