包装类

基本数据类型                       包装类

boolean                             Boolean

byte                                    Byte

short                                  Short

int                                       Integer

long                                   Long

char                                  Character

float                                   Float

double                              Double

1、包装类的默认值都为null

2、8中基本数据类型对应8中包装类

int i= 0；
//基本类型——》包装类：调用包装类的构造方法
Integer a = new Integer(i);