java8 如何实现分组计算数量和计算总数

package com.pig4cloud.pigx.admin.api.vo;

import lombok.Builder;

import lombok.Data;

import lombok.experimental.Tolerate;

import java.util.*;

import java.util.stream.Collectors;

/***

  *

  *Create by 范春宇 on 2019/12/26 17:22

  */

@Data

public class RealSkuVo implements Cloneable{

     private String realEan;

     private Integer realQty;

     public static void main(String[] args) throws CloneNotSupportedException {

         List<RealSkuVo> list = new ArrayList<>();

         RealSkuVo a = new RealSkuVo();

         RealSkuVo b1 = (RealSkuVo)a.clone();

         b1.setRealEan( "asdasda" );

         b1.setRealQty( 1 );

         RealSkuVo b2 = (RealSkuVo)a.clone();

         b2.setRealEan( "asdasda2" );

         b2.setRealQty( 1 );

         RealSkuVo b3 = (RealSkuVo)a.clone();

         b3.setRealEan( "asdasda3" );

         b3.setRealQty( 1 );

         RealSkuVo b4 = (RealSkuVo)a.clone();

         b4.setRealEan( "asdasda3" );

         b4.setRealQty( 1 );

         list.add(b1);

         list.add(b2);

         list.add(b3);

         list.add(b4);

         Map<String, LongSummaryStatistics> collect = list.stream().collect(Collectors.groupingBy(RealSkuVo::getRealEan,Collectors.summarizingLong(RealSkuVo::getRealQty)));

         Map<String, Long> collect1 = list.stream().collect(Collectors.groupingBy(RealSkuVo::getRealEan, Collectors.counting()));

         System.out.println(collect);

     }

}

int [] arr= new int []{ 5 , 1 , 3 , 4 , 1 };

//若统计的是int数组，先转化为List

List<Integer> list= Arrays.stream(arr).boxed().collect(Collectors.toList());

//groupingBy分组

Map<Integer, Long> map = list.stream().collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

//控制台输出map

map.forEach((k,v)->{

       System.out.println( "k=" +k+ ",v=" +v);

});