[Java] 对象排序示例-优快云博客

本文介绍了如何使用Java实现歌曲列表的排序与打印，通过创建一个`Song`类并实现`Comparable`接口来定义比较规则，进而利用Collections.sort方法对歌曲列表进行排序，并通过自定义的`printList`方法打印排序后的歌曲信息。

package test.collections;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

public class Test02 {
    public static void main(String[] args){
        List<Song> songs = new ArrayList<Song>();
        songs.add(new Song(2,"黄家驹","光辉岁月"));
        songs.add(new Song(5,"刘德华","忘情水"));
        songs.add(new Song(44,"张学友","吻别"));
        songs.add(new Song(32,"刘德华","爱你一万年"));
        songs.add(new Song(123,"黄家驹","冷雨夜"));
        songs.add(new Song(133,"小虎队","爱"));
        
        Collections.sort(songs);
        printList(songs);
    }
    public static void printList(Collection<Song> c){
        for(Song song:c){
            System.out.println(song);
        }
    }
}
class Song implements Comparable<Song>{
    private String name;
    private String songer;
    private int id;
    public Song(int id,String songer,String name) {
        super();
        this.id = id;
        this.name = name;
        this.songer = songer;
    }
    
    @Override
    public String toString() {
        return "Song [name=" + name + ", songer=" + songer + ", id=" + id + "]";
    }

    public Song() {
        super();
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSonger() {
        return songer;
    }
    public void setSonger(String songer) {
        this.songer = songer;
    }
    public int compareTo(Song s){
        //使用this.id 和s.id做比较，如果返回值>1,表示顺序排序，返回值是<1的数表示倒序
        if(this.id>s.id){
            return 1;
        }else if(this.id<s.id){
            return -1;
        }else {
            return 0;
        }
        
        //根据歌名排序
        //return this.getName().compareTo(s.getName());
        //根据歌手名排序
        //return this.getSonger().compareTo(s.getSonger());
    }
}