Comparator 排序 ArrayList 实操练习

package ltb6w;

import java.util.Scanner;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Collections;

class GradeStatistic {

Scanner sc=new Scanner(System.in);

private String entername=null ;

private int inputscore = 0;

private List<Mark> al=new ArrayList<Mark>();

private Comparator<Mark> ScoresRanking;
private Comparator<Mark> SortByName;

public GradeStatistic() {

}

class Mark {

private int score;
private String name;

public Mark(String n,int i) {

score=i;
name=n;

}

public int getScore() {

return score;
}

public String getName() {

return name;

}

}

public void enter() throws Exception {

while(true) {

entername= sc.next();

if(entername.equals("over")) {
break;
}

inputscore=sc.nextInt();

al.add(new Mark(entername,inputscore));

System.out.print("姓名:"+this.entername+",分数:"+inputscore+"\n");

}

}

public void getScoresRanking() {

this.ScoresRanking=new ScoresRanking(); //连接上对象

try {
Collections.sort(al,ScoresRanking );
}catch(Exception e) {
e.getMessage();
}

for(int i=0;i<al.size();i++) {

System.out.println("分数排序-->"+"姓名："+al.get(i).getName()+"分数："+al.get(i).getScore());

}
}

public void getSortByName() {

this.SortByName=new SortByName();//连接上对象

try {
Collections.sort(al,SortByName );
}catch(Exception e) {
e.getMessage();
}

for(int j=0;j<al.size();j++) {

System.out.println("姓名排序"+"姓名："+al.get(j).getName()+"分数："+al.get(j).getScore());

}
}

public class ScoresRanking implements Comparator<Mark>{

//分数排序

public int compare(Mark arg0, Mark arg1) {

return (arg0.getScore()<arg1.getScore()?-1:(arg0.getScore()==arg1.getScore()?0:1));

}

}

public class SortByName implements Comparator<Mark> {

//姓名排序

public int compare(Mark m1,Mark m2) {

return (m1.getName().compareTo(m2.getName()));
}
}

public static void main(String[] args) {

GradeStatistic gs= new GradeStatistic();

System.out.print("输入姓名和分数："+"\n");

try {
gs.enter();
} catch (Exception e) {

e.printStackTrace();
}

gs.getScoresRanking();//分数排序
gs.getSortByName();//姓名排序

}

}