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如何基於Java實現物件List排序

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}

以上就是本文的全部內容,希望對大家的學習有所幫助,也希望大家多多支援我們。