Detailed explanation of code examples of Character class in Java

This article mainly introduces the Character class methods in JAVA in detail. Friends who need it can refer to

When using characters, we usually use the built-in data type char.

Example

char ch = 'a';
// Unicode for uppercase Greek omega character
char uniChar = '\u039A'; 
// 字符数组
char[] charArray ={ 'a', 'b', 'c', 'd', 'e' };

However, in the actual development process, we often encounter the need to use objects instead of built-in data type of situation. In order to solve this problem, the Java language provides a wrapper class Character class for the built-in data type char.

The Character class provides a series of methods to manipulate characters. You can use Character's constructor method to create a Character class object, for example:

Character ch = <a href="http://www.php.cn/wiki/165.html" target="_blank">new</a> Character('a');

In some cases, the Java compiler will automatically create a Character object.

For example, when a char type parameter is passed to a method that requires a Character type parameter, the compiler will automatically convert the char type parameter into a Character object. This feature is called boxing, and the converse is called unboxing.

Example

// Here following primitive char 'a'
// is boxed into the Character object ch
Character ch = 'a';

// Here primitive 'x' is boxed for method test,
// return is unboxed to char 'c'
char c = test('x');

Escape sequence

The character preceded by a backslash (\) represents an escape character, It has special meaning to the compiler.

The following list shows Java's escape sequences:

##\"Insert double quotation marks in the text \\Insert a backslash here in the text

Escape Sequence	Description
\t	Insert a tab key at this point in the text
\b	At this point in the text Insert a back key
\n	and wrap the line in the text
\r	Insert a carriage return
\f	Insert a page feed
\'	Insert single quotation marks in the text

Example

When printing a statement When encountering an escape sequence, the compiler can interpret it correctly

public class Test {
  public static void main(String args[]) {
   System.out.println("She said \"Hello!\" to me.");
  }
}

The above example compilation and running results are as follows:

She said "Hello!" to me.

Character method

The following are the methods of the Character class:

Serial numberMethod and description123##4isUpperCase()##5##isLowerCase() Is it a lowercase lettertoUpperCase()Specify the uppercase form of letterstoLowerCase()Specify the lowercase form of letterstoString() Returns the

	isLetter() Is it a letter
	isDi git() Is it a numeric character
	isWhitespace() Is a space
	Is it an uppercase letter?
	6
	7
	8
	string form of the character. The length of the string is only 1

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