Question

is there any other way to know if the java String contains character-encoding in UTF-8 encoding or not ,like the Arabic words for example .

i tried this code : but does it accurate and make the job ?

char c = 'أ';
int num = (int) c;

if(num> 128)
// then UTF-8 characters exists 

Answer 1

(Assuming UTF-8 == non-ASCII)

What you could do is encode then decode the string in ASCII and compare the result of that with the original. If they’re not equal, there are non-ASCII characters.

However, your own sample would work too (almost, should be >= 128), because the following proves that indeed all chars < 128 are ASCII:

To allow backward compatibility, the 128 ASCII and 256 ISO-8859-1 (Latin 1) characters are assigned Unicode/UCS code points that are the same as their codes in the earlier standards.

 

The first plane (code points U+0000 to U+FFFF) contains the most frequently used characters and is called the Basic Multilingual Plane or BMP. Both UTF-16 and UCS-2 encode valid code points in this range as single 16-bit code units that are numerically equal to the corresponding code points.

(“UTF-16” and “ASCII”, Wikipedia)

And chars are UTF-16 “code units”.

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However, judging from the question in its entirety, you might be better off reading The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!) first.