is there anyway to convert from Double to BigInteger?

问题

Is there anyway to convert from double value to BigInteger?

double doubleValue = 64654679846513164.2;
BigInteger bigInteger = (BigInteger) doubleValue;

I try to cast it but it didn't work.

回答1:

BigInteger is made for holding arbitrary precision integer numbers, not decimals. You can use the BigDecimal class to hold a double.

BigDecimal k = BigDecimal.valueOf(doublevalue);

In general, you cannot type cast a Java primitive into another class. The exceptions that I know about are the classes extending Number, such as the Long and Integer wrapper classes, which allow you to cast an int value into an Integer, and so on.

回答2:

You can convert the double into a BigDecimal and then into a BigInteger:

BigInteger k = BigDecimal.valueOf(doublevalue).toBigInteger();

来源：https://stackoverflow.com/questions/17960186/is-there-anyway-to-convert-from-double-to-biginteger