Java 获取、创建 stream 流操作对象的几种方法

Java 获取、创建 stream 流操作对象的几种方法

package com.zhong.streamdemo.createstreamdemo;

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

/**
 * @ClassName : CreateStream
 * @Description : 创建 stream 操作对象
 * @Author : zhx
 * @Date: 2024-02-08 13:10
 */
public class CreateStream {
    public static void main(String[] args) {
        // 获取 List 对象的 stream 操作对象
        System.out.println("-------------获取 List 对象的 stream 操作对象-------------");
        List<String> arrayList = new ArrayList<>(List.of("小钟", "小王", "王五", "王中王", "大小王", "张三", "李四"));
        Stream<String> listStream = arrayList.stream();
        listStream.forEach(System.out::println);

        // 获取 Set 对象的 stream 操作对象
        System.out.println("-------------获取 Set 对象的 stream 操作对象-------------");
        Set<String> hashSet = new HashSet<>(List.of("小钟", "小王", "王五", "王中王", "大小王", "张三", "李四"));
        Stream<String> setStream = hashSet.stream();
        setStream.forEach(System.out::println);

        // 获取 Map 对象的 stream 操作对象
        System.out.println("-------------获取 Map 对象的 stream 操作对象-------------");
        Map<String, Integer> hashMap = new HashMap<>(Map.of("小钟",1, "小王",2, "王五",3, "王中王",4, "大小王",5, "张三",6, "李四",7));
        // 键 stream 流
        Stream<String> keyStream = hashMap.keySet().stream();
        // 值 stream 流
        Stream<Integer> valueStream = hashMap.values().stream();
        // 整个 stream 流
        Stream<Map.Entry<String, Integer>> mapStream = hashMap.entrySet().stream();
        keyStream.forEach(System.out::println);
        valueStream.forEach(System.out::println);
        mapStream.forEach(System.out::println);

        // 数组创建 stream 流
        System.out.println("-------------数组创建 stream 流-------------");
        String[] names = {"小钟", "小王", "王五", "王中王", "大小王", "张三", "李四"};
        Stream<String> arrStream = Arrays.stream(names);
        arrStream.forEach(System.out::println);

    }
}