一起盡在代碼中学赛，大家可以參考代碼理解stream的各種操作

先把一些正常的中間條件以及結(jié)束條件羅列一下

Intermediate（中間操作）：
map (mapToInt, flatMap 等)楚里、 filter副瀑、 distinct称诗、 sorted倘零、 peek铛绰、 limit舞吭、 skip绰上、 parallel旨怠、 sequential、 unordered

Terminal（結(jié)束操作）：
forEach蜈块、 forEachOrdered鉴腻、 toArray、 reduce百揭、 collect爽哎、 min、 max器一、 count课锌、 anyMatch、 allMatch祈秕、 noneMatch渺贤、 findFirst、 findAny请毛、 iterator

Short-circuiting（快速匹配）：
anyMatch志鞍、 allMatch、 noneMatch方仿、 findFirst述雾、 findAny、 limit

package org.gfu.base.stream;

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

/**
 * jdk1.8 stream application
 *
 * https://stackify.com/streams-guide-java-8/
 * @author 719383495@qq.com | 719383495qq@gmail.com | 有問題可以郵箱或者github聯(lián)系我
 * @date 2019/9/22 12:48
 */
public class StreamMain {

    private static final int HASH_MAP_INIT_SIZE = 16;

    public static void main(String[] args) {
        Map map = new HashMap(HASH_MAP_INIT_SIZE);
        listStreamHandler03(StreamUnit.getStreamUnit());
        mapStreamHandler(map);

    }

    /**
     * stream basic operation
     *
     * @param list
     */
    private static void listStreamHandler(List<StreamUnit> list) {
        List<String> result = list
                .stream()
                .filter(i -> i.name.equals("zhangsan"))
                .map(i -> {
                    StreamUnit su = new StreamUnit();
                    su.name = i.name;
                    su.des = i.des;
                    return su;
                })
                .flatMap(i -> {
                    String[] ss = i.name.split("");
                    return Stream.of(ss);
                })
                .skip(2)
                .limit(5)
//                .peek()
//                .collect(Collectors.toSet())
                .collect(Collectors.toList());

        System.out.println(result);
    }

    /**
     * flatMap and reduce
     *
     * @param list
     */
    private static void listStreamHandler01(List<StreamUnit> list) {
        Optional<String> result = list
                .stream()
                .flatMap(i -> Stream.of(i.name.split("")))
                .reduce(String::concat);
        System.out.println(result);
    }

    /**
     * reduce params:{startValue, result , item}
     *
     * @param list
     */
    private static void listStreamHandler02(List<StreamUnit> list) {
        String result = list
                .stream()
                .flatMap(i -> Stream.of(i.name.split("")))
                .skip(4)
                .reduce("fadsf", String::concat);
        System.out.println(result);
    }

    /**
     * reduce params:{object, result , item}
     *
     * @param list
     */
    private static void listStreamHandler03(List<StreamUnit> list) {
        List<StreamUnit> initList = new ArrayList<>(1);
        List<StreamUnit> result = list.stream()
                .reduce(initList, (acc, i) -> {
                    System.out.println(acc);
                    StreamUnit su = new StreamUnit();
                    su.name = i.toString();
                    acc.add(su);
                    return acc;
                }, (u, i) -> u);
        
        System.out.println(result);
    }

    private static void mapStreamHandler(Map map) {
        map.entrySet().stream();
    }
}
``