在Java 8中组合函数和谓词

Function<Integer, Integer> addOne = x -> x + 1;
Function<Integer, Integer> multiplyByTwo = x -> x * 2;

Function<Integer, Integer> addOneAndMultiplyByTwo = addOne.andThen(multiplyByTwo);

int result = addOneAndMultiplyByTwo.apply(3); // 结果为 8

Function<Integer, Integer> addOne = x -> x + 1;
Function<Integer, Integer> multiplyByTwo = x -> x * 2;

Function<Integer, Integer> multiplyByTwoAndAddOne = addOne.compose(multiplyByTwo);

int result = multiplyByTwoAndAddOne.apply(3); // 结果为 7

Predicate<Integer> isEven = x -> x % 2 == 0;

boolean result = isEven.test(4); // 结果为 true

Predicate<Integer> isEven = x -> x % 2 == 0;
Predicate<Integer> isGreaterThanFive = x -> x > 5;

Predicate<Integer> isEvenAndGreaterThanFive = isEven.and(isGreaterThanFive);

boolean result = isEvenAndGreaterThanFive.test(6); // 结果为 true