check if string is utf-8

[alan_sec]

Hi.
Is there any method or class in java for checking if string is utf-8
encoded?
I have to check if string is utf-8 encoded, and if not I have to
replace non-utf-8 characters with "?".
Any suggestion would be nice.
Thanks.
Alan

 

[Guest]

Is there any method or class in java for checking if string is utf-8
encoded?
I have to check if string is utf-8 encoded, and if not I have to
replace non-utf-8 characters with "?".

Do you have a byte[] you need to check it is valid UTF-8 ?

Or do you have a String (which is always UTF-16 internally !) and
want to check if you have converted UTF-8 bytes as if they were
ISO-8859-1 bytes ?

Or ?

Arne

 

[alan_sec]

I have a byte []I need to check if it is valid UTF-8.

 

[=?ISO-8859-1?Q?Arne_Vajh=F8j?=]

I have a byte []I need to check if it is valid UTF-8.

There are some useful stuff in java.nio !

I don't know your context, but here are a code
snippet to illustrate one of the possibilities:

public static boolean test(byte[] b, String csnam) {
CharsetDecoder cd =
Charset.availableCharsets().get(csnam).newDecoder();
try {
cd.decode(ByteBuffer.wrap(b));
} catch (CharacterCodingException e) {
return false;
}
return true;
}

It is probably not the best for your application, because
you could do the conversion and specify replacement etc..

Arne

 

[Chris Uppal]

Is there any method or class in java for checking if string is utf-8
encoded?

Strings (instances of java.lang.String) are /never/ UTF8 encoded. The only
kind of data that can possibly be UTF8 is binary data (such as a byte[] array).

(OK, you /can/ use instances of java.lang.String to hold binary data, but its a
/really bad/ idea.)

I have to check if string is utf-8 encoded, and if not I have to
replace non-utf-8 characters with "?".

That doesn't really make any sense, perhaps you could say more about what you
are trying to do, where your data comes from (how you are reading it), and how
you represent it in your program.

-- chris

 

[Tor Iver Wilhelmsen]

Is there any method or class in java for checking if string is utf-8
encoded?
I have to check if string is utf-8 encoded, and if not I have to
replace non-utf-8 characters with "?".

The String constructor will do that for you - or use the class that
String() refers to in the javadocs.