Shulou(Shulou.com)06/03 Report--

This article introduces the relevant knowledge of "how many bytes are occupied by char [] and String types in Java". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

In C language

1. How many bytes does this a take in char a [10] = {"China"}?

Answer: it takes up 10 bytes.

Parsing: the above code assigns a value to a

A [0] ='C', a [1] ='h', a [2] ='i', a [3] ='n', a [4] ='a', a [5] ='\ 0century] a [6] =''\ 0century force a [7] ='\ 0century law a [8] ='\ 0century month a [9] ='\ 0'

So, it takes up 10 bytes.

2. If you only refer to "China"?

A: a total of 6 bytes. China occupies 5 bytes and ends with'\ 0', accounting for 1 byte.

In the Java language

1. String s = "China"; how many bytes?

Answer: it takes up 5 bytes.

System.out.println (Charset.defaultCharset ()); / / get ide default encoding type String s = new String ("China" .getBytes ()); byte [] b = s.getBytes (); System.out.println ("" + b.length)

With the above code, you can output "China" with a byte length of 5.

2. String s = "China"; how many bytes?

A: in the case of Chinese characters, you need to consider coding.

(1) when GBK coding (ide default), each Chinese character occupies 2 bytes, then China occupies 4 bytes.

(2) when UTF-8 coding, each Chinese character occupies 3 bytes, then China occupies 6 bytes.

3. Transcoding problem: will the byte footprint become larger when GBK is converted to UTF-8? And the other way around?

/ / get UTF-8 code System.out.println (Charset.defaultCharset ()); String sporttry {s = new String ("China" .getBytes (), "GBK"); byte [] b = s.getBytes (); System.out.println ("" + b.length);} catch (UnsupportedEncodingException e) {e.printStackTrace ();}

As the above code is: UTF-8 to GBK encoding format, s length from 6 bytes to 9 bytes.

S content change: China-> trickle 

Because the current encoding is UTF-8, it becomes 3 words after transcoding, occupying 9 bytes. However, the opposite goes like this:

China (gbk)? (utf-8)

The length of s has changed from 4 bytes to 4 bytes, although the length has not changed, but the text has changed. Here? Occupies 1 byte.

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