Java如何从集合和数组获取Stream流的方法

import java.util.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        // 创建集合
        List<String> list = Arrays.asList("A", "B", "C");

        // 获取顺序流
        Stream<String> stream = list.stream();
        stream.forEach(System.out::println);

        // 获取并行流
        Stream<String> parallelStream = list.parallelStream();
        parallelStream.forEach(System.out::println);
    }
}

import java.util.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        // 创建数组
        String[] array = { "A", "B", "C", "D" };

        // 将整个数组转换为流
        Stream<String> stream = Arrays.stream(array);
        stream.forEach(System.out::println);

        // 将数组部分范围转换为流
        Stream<String> partialStream = Arrays.stream(array, 1, 3);
        partialStream.forEach(System.out::println); // 输出 B, C
    }
}

import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        // 使用 Stream.of 从元素生成流
        Stream<String> stream = Stream.of("A", "B", "C");
        stream.forEach(System.out::println);

        // 使用 Stream.of 从数组生成流
        String[] array = { "X", "Y", "Z" };
        Stream<String> arrayStream = Stream.of(array);
        arrayStream.forEach(System.out::println);
    }
}

import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        // 使用 IntStream.of
        IntStream intStream = IntStream.of(1, 2, 3, 4);
        intStream.forEach(System.out::println);

        // 使用 Arrays.stream
        int[] intArray = { 5, 6, 7, 8 };
        IntStream arrayStream = Arrays.stream(intArray);
        arrayStream.forEach(System.out::println);
    }
}

import java.util.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        // 创建 Map
        Map<String, Integer> map = new HashMap<>();
        map.put("A", 1);
        map.put("B", 2);
        map.put("C", 3);

        // 获取键流
        Stream<String> keyStream = map.keySet().stream();
        keyStream.forEach(System.out::println);

        // 获取值流
        Stream<Integer> valueStream = map.values().stream();
        valueStream.forEach(System.out::println);

        // 获取键值对流
        Stream<Map.Entry<String, Integer>> entryStream = map.entrySet().stream();
        entryStream.forEach(entry -> System.out.println(entry.getKey() + ": " + entry.getValue()));
    }
}