类对象数组以及排序问题

package java作业;

import java.util.Arrays;

 class BankAccount implements Comparable{ //实现了Comparable接口后可以调用Arrays.sort方法

  double money;

  String BankNum;

  BankAccount(double money,String BankNum){

   this.money=money;

   this.BankNum=BankNum;

  }

 public int compareTo(Object o) { //Comparable中定义的方法

  BankAccount a=(BankAccount) o;

/* 按升序排列*/

  if(money<a.money)

   return -1;

  else if (money>a.money)

   return 1;

  else

  return 0;

 }

/*降序排列

if(money<a.money)

   return 1;

  else if (money>a.money)

   return -1;

  else

  return 0;

 */

}

public class TestBankAccount {

 public static void main(String[] args) {

  // TODO 自动生成的方法存根

  BankAccount []list=new BankAccount[3];

  list[0]=new BankAccount(2000,"123456");

  list[1]=new BankAccount(1000,"123457");

  list[2]=new BankAccount(3000,"123459");

  Arrays.sort(list);

  int i=0;

  for(i=0;i<list.length;i++){

   System.out.println("money:"+list[i].money+",BankNum:"+list[i].BankNum);

  }

 }

}

输出结果：money:1000.0,BankNum:123457

money:2000.0,BankNum:123456

money:3000.0,BankNum:123459