Java api ------ Number class and Character class, javacharacterapi

Java api ------ Number class and Character class, javacharacterapi

Java basic data types include: boolean, byte, short, int, long, double, float, char, among them, byte, short, int, long, double, and float are also called Number classes. Java also provides classes related to basic data types, as follows:

Basic Type	Boolean	Byte	Short	Int	Long	Double	Float	Char
Corresponding packaging class	Boolean	Byte	Short	Integer	Long	Double	Float	Chracter

These classes have similar constructor forms: Class Name (basic type value). Both the Number class and the Chracter class provide the conversion method between them and the String class. In addition, the Chracter class provides some other methods:

For example, isLetter () determines whether isDiqit () determines whether it is an array isWhiteSpace () and whether isUpperCase () is an upper-case letter isLowerCase () or a lower-case letter.

ToUpperCase () is converted into uppercase letters toLowerCase () and lowercase letters.