Java Character class

The Character class is used to operate on a single character.

The Character class wraps the value of a primitive type char in an object

Examples

char ch = ' a ' ; // Unicode character representation char uniChar = ' \u 039A ' ; // array of characters char [ ] charArray = { ' a ' , ' b ' , ' c ' , ' d ' , ' e ' } ;

However, in the actual development process, we often encounter the need to use the object, rather than the built-in data type. To solve this problem, the Java language provides a wrapper class Character for the built-in data type char.

The Character class provides a series of methods for manipulating characters. You can use the Character constructor to create a Character object, for example:

Character ch = new Character ( ' a ' ) ;

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

For example, when you pass a parameter of char type to a method that requires a Character type parameter, the compiler automatically converts the char type parameter to a Character object. This feature is called packing, which in turn is called unboxing.

Examples

//The original character 'a' is boxed into the Character object ch Character ch = ' a ' ; // original character 'x' boxed with test method // Return unboxing values ​​to 'c' char c = test ( ' x ' ) ;

---

Escape sequence

Characters preceded by a backslash (\) represent escape characters, which have special meaning to the compiler.

The following list shows Java's escape sequences:

Escape sequence	description
\t	Insert a tab key here in the text
\b	Insert a back key here in the text
\n	Wrap this place in the text
\r	Insert a carriage return here
\f	Insert a page break here in the text
\'	Insert single quotes there
\"	Insert double quotes in the text
\\	Insert a backslash there

Examples

When the print statement encounters an escape sequence, the compiler can interpret it correctly.

The following example escapes double quotes and outputs:

Test.java file code:

public class the Test {

public static void main ( String args [ ] ) {

System.out.println( " Visit \" Rookies Tutorial! \ " " ) ; }

}

The above example compiled and run results are as follows:

Visit "Rookies Tutorial!"

---

Character method

Here is the method of the Character class:

No.	Method and description
1	IsLetter() is a letter
2	IsDigit() is a numeric character
3	isWhitespace() is a space
4	IsUpperCase() is an uppercase letter
5	IsLowerCase() is a lowercase letter
6	toUpperCase() Specifies the capitalization of letters
7	toLowerCase ()  Specifies the lowercase of the letter
8	toString ()  returns the character string, the length of the string is only 1

For a complete list of methods, please refer to the java.lang.Character API specification.