java 对象数组排序

import java.util.*;

import java.io.*;



public class Main{

static int [] dp = new int [1010];

public static void main(String [] args)throws IOException{

Mouse [] mice = new Mouse [1010];

FileReader fr=new FileReader("in.txt");   //读取文件

BufferedReader read = new BufferedReader(fr);

String str = "";

int n=1;

while((str = read.readLine())!=null){

String [] s= str.split(" ");

mice[n] = new Mouse();   //对象实例化，很重要

mice[n].weight = Integer.parseInt(s[0]);

mice[n].speed =Integer.parseInt(s[1]);

n++;

}

System.out.println(n);

Arrays.sort(mice,1,n);   //sort(int start,int end)  包括start索引，不包括end索引

for(int i=1;i<n;i++){

System.out.println(mice[i].weight+" "+mice[i].speed);

}

}

}

class Mouse implements Comparable{   //实现Comparable接口

int weight;

int speed;

public int compareTo(Object o){     //重写compareTo方法

Mouse m=(Mouse)o;

return weight>m.weight?1:(weight==m.weight?0:-1);

}

}