java备忘录之大数值

BigInteger b =BigInteger.valueOf(1000);
BigDecimal d = BigDecimal.valueOf(100.0);

BigInteger add(BigInteger other)            //加
BigInteger subtract(BigInteger other)       //减
BigInteger multipy(BigInteger other)        //乘
BigInteger div(BigInteger other)            //除
BigInteger mod(BigInteger other)            //取余
int compareTo(BigInteger other)             //比较，等于返回零，小于返回负数，反之正数
static BigInteger valueOf(long x)           //返回等于x的大整数