java8使用stream进行排序(多字段排序、升序、降序)--688IT编程网

java8使⽤stream进⾏排序（多字段排序、升序、降序）⽂章包含“标题”、“发布时间”、“是否推荐”、“是否置顶”四个属性。

import AllArgsConstructor;

import Data;

import NoArgsConstructor;

@Data

@NoArgsConstructor

@AllArgsConstructor

public class Article {

/**

* ⽂章标题

private String title;

/**

* 发布时间

private String releaseTime;

/**

* 是否推荐：Y 推荐；N 不推荐

private String recommend;

/**

* 是否置顶: Y 置顶；N 不置顶

private String top;

}

测试代码

import ArrayList;

import Comparator;

import List;

import Collectors;

public class Demo {

public static void main(String[] args){

List<Article> list =init();

sort(list);

sort2(list);

}

/**

* 初始化数据

* @return

private static List<Article>init(){

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

list.add(new Article("⽂章⼀","2021-11-01","Y","Y"));

list.add(new Article("⽂章⼆","2021-11-02","Y","Y"));

list.add(new Article("⽂章三","2021-11-01","Y","N"));

list.add(new Article("⽂章⼀","2021-11-02","Y","N"));

list.add(new Article("⽂章⼀","2021-11-01","N","Y"));

list.add(new Article("⽂章⼀","2021-11-02","N","Y"));

list.add(new Article("⽂章⼀","2021-11-01","N","N"));

list.add(new Article("⽂章⼀","2021-11-02","N","N"));

return list;

}

....

}

排序⽅法

* 按照推荐、置顶、发布时间来排序

* @param list

private static void sort(List<Article> list){

List<Article> sortList = list.stream()

// 【X】

.sorted(Comparatorparing(Article::verseOrder())

// 【Y】

.thenComparing(Article::verseOrder())

// 【Z】

thenComparing(Article::verseOrder()))

.List());

sortList.stream().forEach(System.out::println);

}

// 运⾏结果：

// Article(title=⽂章⼆, releaseTime=2021-11-02, recommend=Y, top=Y)

// Article(title=⽂章⼀, releaseTime=2021-11-01, recommend=Y, top=Y)

// Article(title=⽂章⼀, releaseTime=2021-11-02, recommend=Y, top=N)

// Article(title=⽂章三, releaseTime=2021-11-01, recommend=Y, top=N)

java stream// Article(title=⽂章⼀, releaseTime=2021-11-02, recommend=N, top=Y)

// Article(title=⽂章⼀, releaseTime=2021-11-01, recommend=N, top=Y)

/ Article(title=⽂章⼀, releaseTime=2021-11-02, recommend=N, top=N)

// Article(title=⽂章⼀, releaseTime=2021-11-01, recommend=N, top=N)

【X】：优先使⽤recommend字段排序，并且使⽤降序排列(verseOrder())，在结果中的体现是前四篇⽂章的recommend为‘Y’，后四篇的recommend为‘N’

【Y】：之后再使⽤top字段排序，并且使⽤降序排列(verseOrder()), 在结果中的体现是recommend相同的⽂章中，前两篇⽂章的top为‘Y’, 后两篇⽂章的top为‘N’

【Z】：最后使⽤发布时间字段进⾏排序，并且使⽤降序排列(verseOrder())

两种倒序⽅式

Comparatorparing(类:：属性,verseOrder()）

/**

* 按照推荐、置顶、发布时间来排序

* @param list

private static void sort(List<Article> list){

List<Article> sortList = list.stream()

// 【X】

.sorted(Comparatorparing(Article::verseOrder())

// 【Y】

.thenComparing(Article::verseOrder())

// 【Z】

.thenComparing(Article::verseOrder()))

.List());

sortList.stream().forEach(System.out::println);

}

// 运⾏结果：

// Article(title=⽂章⼆, releaseTime=2021-11-02, recommend=Y, top=Y)

// Article(title=⽂章⼀, releaseTime=2021-11-01, recommend=Y, top=Y)

// Article(title=⽂章⼀, releaseTime=2021-11-02, recommend=Y, top=N)

// Article(title=⽂章三, releaseTime=2021-11-01, recommend=Y, top=N)

// Article(title=⽂章⼀, releaseTime=2021-11-02, recommend=N, top=Y)

// Article(title=⽂章⼀, releaseTime=2021-11-01, recommend=N, top=Y)

// Article(title=⽂章⼀, releaseTime=2021-11-02, recommend=N, top=N)

// Article(title=⽂章⼀, releaseTime=2021-11-01, recommend=N, top=N)

以传⼊的字段进⾏倒序排列

【X】：这⾥就类似于mysql中的 order by recommend desc

【Y】：结合【X】就是order by recommend desc, top desc

Comparatorparing(Article::verseOrder()).reversed()

private static void sort2(List<Article> list){

List<Article> sortList = list.stream()

.sorted(Comparatorparing(Article::verseOrder())

.thenComparing(Article::verseOrder())

.thenComparing(Article::verseOrder()).reversed())// 【X】

.List());

sortList.stream().forEach(System.out::println);

}

/ 运⾏结果：