Java-8: boolean primitive array to stream?

问题:

There is no nice way to convert given boolean[] foo array into stream in Java-8 in one statement, or am I missing something?

(I will not ask why?, but it is really incomprehensible: why not add stream support for all primitive types?)

Hint: Arrays.stream(foo) will not work, there is no such method for boolean[] type.

回答1:

Given boolean[] foo use

Stream<Boolean> stream = IntStream.range(0, foo.length)
                                  .mapToObj(idx -> foo[idx]);

Note that every boolean value will be boxed, but it's usually not a big problem as boxing for boolean does not allocate additional memory (just uses one of predefined values - Boolean.TRUE or Boolean.FALSE).

回答2:

You can use Guava's Booleans class:

Stream<Boolean> stream = Booleans.asList(foo).stream();

This is a pretty efficient way because Booleans.asList returns a wrapper for the array and does not make any copies.