常常遇到数组排序的问题.比如我有一个Person类,它的实例对象存储在ArrayList数组中,现在要把ArrayList数组中的Person对象按照年龄排序.
其实这种情况经常遇到.
下面给出源代码:

1:Person.java文件:-------------------------------
public class Person{
 String name;
 int age;
 
 public Person(String name,int age){
  this.name = name;
  this.age = age;
  
 }

 public int getAge() {
  return age;
 }

 public void setAge(int age) {
  this.age = age;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

}

2:Mycomparator.java-------------------------------
//实现Comparator接口,也就是定义排序规则,你几乎可以定义任何规则
package com.infoearth;
import java.util.*;
public class Mycomparator implements Comparator{

 public int compare(Object o1,Object o2) {
  Person p1=(Person)o1;
  Person p2=(Person)o2;  
  if(p1.age<p2.age)
   return 1;
  else
   return 0;
 }

}

3:ListSort.java------------------------------------

package com.infoearth;

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

public class ListSort {
 public static void main(String[] args){
  ArrayList list = new ArrayList();
  list.add(new Person("lcl",28));
  list.add(new Person("fx",23));
  list.add(new Person("wqx",29));
  Comparator comp = new Mycomparator();
  Collections.sort(list,comp);  
  for(int i = 0;i<list.size();i++){
   Person p = (Person)list.get(i);
   System.out.println(p.getName());
  }  
  
 }

}