自动装、拆箱

int i = 1;
Integer integer = new Integer(1);
Object obj = integer;

i = integer;
integer = i;

obj = i;
i = (Integer)obj;
i = (int)obj;	//错误
i = obj;		//错误

int i = 1;
Int32 int32 = new Int32();
Object obj = int32;

i = int32;
int32 = i;

obj = i;
i = (Int32)obj;
i = (int)obj;
i = obj;		//错误