一起尽在代码中，大家可以参考代码理解stream的各种操作

先把一些正常的中间条件以及结束条件罗列一下

Intermediate（中间操作）：
map (mapToInt, flatMap 等)、 filter、 distinct、 sorted、 peek、 limit、 skip、 parallel、 sequential、 unordered

Terminal（结束操作）：
forEach、 forEachOrdered、 toArray、 reduce、 collect、 min、 max、 count、 anyMatch、 allMatch、 noneMatch、 findFirst、 findAny、 iterator

Short-circuiting（快速匹配）：
anyMatch、 allMatch、 noneMatch、 findFirst、 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 | 有问题可以邮箱或者github联系我
 * @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();
    }
}
``