list分组统计

package com.example.demo.controller;

import com.alibaba.fastjson.JSON;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

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

/**
 * @author yhyi 2020/7/23 16:04
 * @ClassName TestDemo.java
 * @Description
 * @version V1.0
 * @modificationHistory=========================逻辑或功能性重大变更记录
 * @modify by user: {修改人} 2020/7/23
 * @modify by reason:{方法名}:{原因}
 */
public class TestDemo {

    public static void main(String[] args) {
        List<Test> list = Lists.newArrayList();
        Test map = new Test("研发部","x");
        Test map2 = new Test("研发部","y");
        Test map3 = new Test("研发部","z");
        Test map4 = new Test("测试部","x");
        Test map5 = new Test("测试部","y");
        Test map6 = new Test("测试部","z");
        Test map7 = new Test("测试部","q");
        list.add(map);
        list.add(map);
        list.add(map);
        list.add(map2);
        list.add(map2);
        list.add(map3);
        list.add(map4);
        list.add(map5);
        list.add(map5);
        list.add(map6);
        list.add(map7);
        Map<String, List<Test>> collect = list.stream().collect(Collectors.groupingBy(e -> e.getDept()));
        List<Object> setList = Lists.newArrayList();
        collect.forEach((mapKey, getValue) -> {
            Map<Object, Object> setMap = Maps.newHashMap();
            //key:原因  value：数量
            Map<String, Long> longMap = getValue.stream().collect(Collectors.groupingBy(Test::getReson, Collectors.counting()));
            //key:原因 value：数量  排序后的
            Map<String, Long> setMap1 = longMap.entrySet().stream().sorted(Map.Entry.<String, Long>comparingByValue().reversed()).collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (a, b) -> b, LinkedHashMap::new));
            //key：部门 value：原因+条数
            setMap.put(mapKey, setMap1);
            setList.add(setMap);
        });
        System.out.println("JSON.toJSONString(setList) = " + JSON.toJSONString(setList));

    }

}
class Test{
    private String dept;//部门
    private String  reson;//原因

    public String getDept() {
        return dept;
    }

    public void setDept(String dept) {
        this.dept = dept;
    }

    public String getReson() {
        return reson;
    }

    public void setReson(String reson) {
        this.reson = reson;
    }

    public Test(String dept, String reson) {
        this.dept = dept;
        this.reson = reson;
    }
}