Java Lambda表达式的使用详解

(参数列表) -> { 方法体 }

List<String> list = Arrays.asList("Java", "Python", "C++");
Collections.sort(list, new Comparator<String>() {
    @Override
    public int compare(String s1, String s2) {
        return s1.compareTo(s2);
    }
});
System.out.println(list);

List<String> list = Arrays.asList("Java", "Python", "C++");
list.sort((s1, s2) -> s1.compareTo(s2));
System.out.println(list);

Runnable runnable = () -> System.out.println("无参数的Lambda表达式");
new Thread(runnable).start();

Consumer<String> consumer = s -> System.out.println(s);
consumer.accept("单个参数的Lambda表达式");

BiFunction<Integer, Integer, Integer> sum = (a, b) -> a + b;
System.out.println(sum.apply(5, 10));

Function<Integer, Integer> square = x -> x * x;
System.out.println(square.apply(4));

BiFunction<Integer, Integer, Integer> multiply = (a, b) -> {
    int result = a * b;
    System.out.println("结果：" + result);
    return result;
};
multiply.apply(3, 4);

@FunctionalInterface
public interface MyFunctionalInterface {
    void show();
}

MyFunctionalInterface myInterface = () -> System.out.println("Lambda实现函数式接口");
myInterface.show();

import java.util.function.*;

public class LambdaDemo {
    public static void main(String[] args) {
        // Consumer示例
        Consumer<String> consumer = s -> System.out.println("消费：" + s);
        consumer.accept("Java");

        // Supplier示例
        Supplier<String> supplier = () -> "提供数据";
        System.out.println(supplier.get());

        // Function示例
        Function<Integer, String> function = i -> "数字：" + i;
        System.out.println(function.apply(10));

        // Predicate示例
        Predicate<Integer> predicate = n -> n > 5;
        System.out.println(predicate.test(10));
    }
}

List<String> list = Arrays.asList("Java", "Python", "C++");

// 普通遍历
for (String item : list) {
    System.out.println(item);
}

// 使用Lambda表达式
list.forEach(s -> System.out.println(s));

Map<String, Integer> map = new HashMap<>();
map.put("Java", 1);
map.put("Python", 2);
map.put("C++", 3);

// Lambda遍历Map
map.forEach((k, v) -> System.out.println(k + " -> " + v));

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8);

// 筛选偶数并计算平方
List<Integer> squares = numbers.stream()
        .filter(n -> n % 2 == 0)
        .map(n -> n * n)
        .collect(Collectors.toList());

System.out.println(squares);

int num = 10;
Runnable r = () -> System.out.println(num);
r.run();

@FunctionalInterface
interface ThrowingConsumer<T> {
    void accept(T t) throws Exception;
}