如何基於Java實現物件List排序
阿新 • • 發佈:2020-01-15
這篇文章主要介紹瞭如何基於Java實現物件List排序,文中通過示例程式碼介紹的非常詳細,對大家的學習或者工作具有一定的參考學習價值,需要的朋友可以參考下
按照物件中的某個屬性,對物件List進行排序。
以初唐四傑的成績排名為例,對詩人進行排序。
Java實現如下:
1、詩人(Poet)類結構,定義如下:
/** * Created by Miracle Luna on 2020/1/11 */ public class Poet { private String name; private Double score; public Poet(String name,Double score) { this.name = name; this.score = score; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Double getScore() { return score; } public void setScore(Double score) { this.score = score; } @Override public String toString() { return "Poet{" + "name='" + name + '\'' + ",score=" + score + '}'; } }
2、詩人按照成績排名,程式碼如下:
import java.util.ArrayList; import java.util.Comparator; import java.util.List; /** * Created by Miracle Luna on 2020/1/11 */ public class PoetSort { public static void main(String[] args) { List<Poet> poetList = new ArrayList<Poet>(); Poet poet1 = new Poet("楊炯",94.0); poetList.add(poet1); Poet poet2 = new Poet("盧照鄰",92.5); poetList.add(poet2); Poet poet3 = new Poet("駱賓王",95.0); poetList.add(poet3); Poet poet4 = new Poet("王勃",99.5); poetList.add(poet4); // 初始順序 System.out.println("==> 初始順序如下:"); poetList.forEach(poet -> System.out.println(poet.toString())); // 按照分數排名(從高到低) poetList.sort(new Comparator<Poet>() { @Override public int compare(Poet poet1,Poet poet2) { Double score1 = poet1.getScore(); Double score2 = poet2.getScore(); return score2.compareTo(score1); } }); System.out.println("\n==> 按照分數排名(從高到低)如下:"); poetList.forEach(poet -> System.out.println(poet.toString())); // 按照分數排名(從低到高) poetList.sort(new Comparator<Poet>() { @Override public int compare(Poet poet1,Poet poet2) { Double score1 = poet1.getScore(); Double score2 = poet2.getScore(); return score1.compareTo(score2); } }); System.out.println("\n==> 按照分數排名(從低到高)如下:"); poetList.forEach(poet -> System.out.println(poet.toString())); } }
3、執行結果如下:
==> 初始順序如下: Poet{name='楊炯',score=94.0} Poet{name='盧照鄰',score=92.5} Poet{name='駱賓王',score=95.0} Poet{name='王勃',score=99.5} ==> 按照分數排名(從高到低)如下: Poet{name='王勃',score=99.5} Poet{name='駱賓王',score=95.0} Poet{name='楊炯',score=92.5} ==> 按照分數排名(從低到高)如下: Poet{name='盧照鄰',score=92.5} Poet{name='楊炯',score=94.0} Poet{name='駱賓王',score=99.5}
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