List的排序是經(jīng)常遇到的問題，一般都是用一個(gè)實(shí)現(xiàn)了Comparator接口的類實(shí)現(xiàn)。
.比如我有一個(gè)Person類,
它的實(shí)例對象存儲在ArrayList數(shù)組中,現(xiàn)在要把ArrayList數(shù)組中的Person對象按照年齡排序.
其實(shí)這種情況經(jīng)常遇到.
下面給出源代碼:

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-------------------------------
//實(shí)現(xiàn)Comparator接口,也就是定義排序規(guī)則,你幾乎可以定義任何規(guī)則
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------------------------------------

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());
? }?
?
?}

}