Java 数据类型

Integer Types

Type	Storage Requirement	Range (Inclusive)
Int	4 bytes	–2,147,483,648 to 2,147,483, 647 (just over 2 billion)
Short	2 bytes	–32,768 to 32,767
Long	8 bytes	–9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
Byte	1 byte	–128 to 127

八进制      ：0x
十六进制 ：0
声明一个long的需要加上l/L

Float-Point Types

Type	Storage Requirement	Range
float	4 bytes	approximately ±3.40282347E+38F (6–7 significant decimal digits)
double	8 bytes	approximately ±1.79769313486231570E+308 (15 significant decimal digits)

float要用f/F指定