dk为lambda表达式已经内置了丰富的函数式接口，如下表所示(仅列出部分)：
函数式接口 函数描述符 原始类型特化
Predicate<T> T -> boolean IntPredicate, LongPredicate, DoublePredicate
Consumer<T> T -> void IntConsumer, LongConsumer, DoubleConsumer
Funcation<T, R> T -> R IntFuncation<R>, IntToDoubleFunction, IntToLongFunction<R>, LongFuncation…
Supplier<T> () -> T BooleanSupplier, IntSupplier, LongSupplier, DoubleSupplier
UnaryOperator<T> T -> T IntUnaryOperator, LongUnaryOperator, DoubleUnaryOperator
BinaryOperator<T> (T, T) -> T IntBinaryOperator, LongBinaryOperator, DoubleBinaryOperator
BiPredicate<L, R> (L, R) -> boolean
BiConsumer<T, U> (T, U) -> void
BiFunction<T, U, R> (T, U) -> R