Explanation of Conversion Between Character Array and String in Java and StringBuilder and String

  • 2021-07-03 00:07:37
  • OfStack

1. String- > Character array:


String str =  " abc "; 
char[] a = str.toCharArray();

Memory: String is a class, so use built-in functions

Extension:


char b = str.charAt(1);
str.length();
a.length;

2. Character Array- > String:


String str = String.valueOf(a) ; 

Memory: Similar to Cast Format, String (a)

Extension: Character to Character Class


Character c = Character.valueOf(a[1]);

3. Character Array- > StringBuilder:


StringBuilder sb = new StringBuilder();
for(int i = 0; i < a.length; i++)
sb.append(a[i]);

Hard conversion only

4. String- > StringBuilder:


StringBuilder sb = new StringBuilder(str)

Memory: When initializing

5. StringBuilder- > String:


String str = sb.toString();

Memory: and string to character array 1, built-in function, pay attention to parentheses! And string str.length() 1 sample

6. StringBuilder deletion


sb.delete(0,n)

Delete elements from 0 to n-1.

Summarize


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