[Encoding] Difference btw UTF-8 and Unicode

출처 : http://rrn.dk/the-difference-between-utf-8-and-unicode

요약 : In UTF-8, characters from the U+0000..U+10FFFF range (the UTF-16 accessible range) are encoded using sequences of 1 to 4 octets.

Character		Binary code point	Binary UTF-8	Hexadecimal UTF-8
$	U+0024	0100100	00100100	24
¢	U+00A2	000 10100010	11000010 10100010	C2 A2
€	U+20AC	00100000 10101100	11100010 10000010 10101100	E2 82 AC
𤭢	U+24B62	00010 01001011 01100010	11110000 10100100 10101101 10100010	F0 A4 AD A2

The difference between UTF-8 and Unicode?

May 2010

If asked the question, "What is the difference between UTF-8 and Unicode?", would you confidently reply with a short and precise answer? In these days of internationalization all developers should be able to do that. I suspect many of us do not understand these concepts as well as we should. If you feel you belong to this group, you should read this ultra short introduction to character sets and encodings.
Actually, comparing UTF-8 and Unicode is like comparing apples and oranges:
UTF-8 is an encoding - Unicode is a character set
A character set is a list of characters with unique numbers (these numbers are sometimes referred to as "code points"). For example, in the Unicode character set, the number for A is 41.
An encoding on the other hand, is an algorithm that translates a list of numbers to binary so it can be stored on disk. For example UTF-8 would translate the number sequence 1, 2, 3, 4 like this:

00000001 00000010 00000011 00000100

Our data is now translated into binary and can now be saved to disk.

All together now

Say an application reads the following from the disk:

1101000 1100101 1101100 1101100 1101111

The app knows this data represent a Unicode string encoded with UTF-8 and must show this as text to the user. First step, is to convert the binary data to numbers. The app uses the UTF-8 algorithm to decode the data. In this case, the decoder returns this:

104 101 108 108 111

Since the app knows this is a Unicode string, it can assume each number represents a character. We use the Unicode character set to translate each number to a corresponding character. The resulting string is "hello".

Conclusion

So when somebody asks you "What is the difference between UTF-8 and Unicode?", you can now confidently answer short and precise:
UTF-8 and Unicode cannot be compared. UTF-8 is an encoding used to translate binary data into numbers. Unicode is a character set used to translate numbers into characters.