Java8中常见函数式接口的使用示例详解

import java.util.function.Consumer;

Consumer<String> printConsumer = System.out::println;
printConsumer.accept("Hello, World!");

import java.util.function.Supplier;

Supplier<Double> randomSupplier = Math::random;
System.out.println(randomSupplier.get());

import java.util.function.Function;

Function<String, Integer> lengthFunction = String::length;
System.out.println(lengthFunction.apply("Hello"));

import java.util.function.Predicate;

Predicate<String> nonEmptyStringPredicate = (String s) -> !s.isEmpty();
System.out.println(nonEmptyStringPredicate.test("Test"));

Function<Integer, Integer> times2 = e -> e * 2;
Function<Integer, Integer> squared = e -> e * e;

Function<Integer, Integer> times2AndSquare = times2.andThen(squared);
System.out.println(times2AndSquare.apply(4)); // 输出 64

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

Predicate<Integer> isEvenAndPositive = isEven.and(isPositive);
System.out.println(isEvenAndPositive.test(4)); // true

import java.util.function.UnaryOperator;

UnaryOperator<Integer> square = x -> x * x;
System.out.println(square.apply(5)); // 输出 25

import java.util.function.BiFunction;

BiFunction<Integer, Integer, Integer> add = (a, b) -> a + b;
System.out.println(add.apply(2, 3)); // 输出 5

import java.util.function.BinaryOperator;

BinaryOperator<Integer> multiply = (a, b) -> a * b;
System.out.println(multiply.apply(3, 4)); // 输出 12

import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

class ComplexClass {
    private int value;

    ComplexClass(int value) {
        this.value = value;
    }

    // Getter and other methods...
}

Function<Integer, ComplexClass> complexClassFactory = ComplexClass::new;
ComplexClass complexInstance = complexClassFactory.apply(10);

UnaryOperator<String> toUpperCase = String::toUpperCase;
UnaryOperator<String> addExclamation = str -> str + "!";

UnaryOperator<String> shout = toUpperCase.andThen(addExclamation);
System.out.println(shout.apply("hello")); // 输出 "HELLO!"

import java.util.function.BiConsumer;

BiConsumer<String, String> concatAndPrint = (a, b) -> System.out.println(a + b);
concatAndPrint.accept("Hello, ", "World!"); // 输出 Hello, World!

import java.util.function.BiPredicate;

BiPredicate<Integer, String> validate = (i, s) -> i > 0 && s.startsWith("A");
System.out.println(validate.test(1, "Apple")); // 输出 true

import java.util.function.ToIntFunction;

ToIntFunction<String> length = String::length;
System.out.println(length.applyAsInt("Hello")); // 输出 5