Java8 Steam中预定义的函数式接口

Java8预定义函数式接口

函数式接口	函数描述符	原始类型特化
Predicate	T->boolean	IntPredicate,LongPredicate, DoublePredicate
Consumer	T->void	IntConsumer,LongConsumer, DoubleConsumer
Function<T,R>	T->R	IntFunction< R >,IntToDoubleFunction,IntToLongFunction,LongFunction,LongToDoubleFunction,LongToIntFunction,DoubleFunction,ToIntFunction,ToDoubleFunction,ToLongFunction
Supplier	()->T	BooleanSupplier,IntSupplier, LongSupplier,DoubleSupplier
UnaryOperator	T->T	IntUnaryOperator,LongUnaryOperator,DoubleUnaryOperator
BinaryOperator	(T,T)->T	IntBinaryOperator,LongBinaryOperator,DoubleBinaryOperator
BiPredicate<L,R>	(L,R)->boolean
BiConsumer<T,U>	(T,U)->void	ObjIntConsumer,ObjLongConsumer,ObjDoubleConsumer
BiFunction<T,U,R>	(T,U)->R	ToIntBiFunction<T,U>,ToLongBiFunction<T,U>,ToDoubleBiFunction<T,U>

一些常用的Lambda表达式与其对应的函数式接口应用举例：

使用案例	Lambda表达式	对应的函数式接口
布尔表达式	(List list) -> list.isEmpty()	Predicate<List>
创建对象	() -> new Apple(10)	Supplier< Apple >
消费一个对象	(Apple a) -> System.out.println(a.getWeight())	Consumer< Apple >
从一个对象中选择/提取	(String s) -> s.length()	Function< String, Integer >或ToIntFunction< String >
合并两个值	(int a, int b) -> a * b	IntBinaryOperator
比较两个对象	(Apple a1, Apple a2) -> a1.getWeight().compareTo(a2.getWeight())	Comparator< Apple >或BiFunction< Apple, Apple, Integer > 或 ToIntBiFunction< Apple, Apple >