How to convert a double to long without casting?
Assuming you're happy with truncating towards zero, just cast:
double d = 1234.56;long x = (long) d; // x = 1234This will be faster than going via the wrapper classes - and more importantly, it's more readable. Now, if you need rounding other than "always towards zero" you'll need slightly more complicated code.
... And here is the rounding way which doesn't truncate. Hurried to look it up in the Java API Manual:
double d = 1234.56;long x = Math.round(d); //1235
The preferred approach should be:
Double.valueOf(d).longValue()From the Double (Java Platform SE 7) documentation:
Double.valueOf(d)Returns a
Doubleinstance representing the specifieddoublevalue. If a newDoubleinstance is not required, this method should generally be used in preference to the constructorDouble(double), as this method is likely to yield significantly better space and time performance by caching frequently requested values.