ArrayList排序 降序排列

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;
    }
}
import <a href="http://lib.csdn.net/base/17" class='replace_word' title="Java EE知识库" target='_blank' style='color:#df3434; font-weight:bold;'>Java</a>.util.Comparator;
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 -1;
       }
}
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());
         }   
     }
}

看图，关键是定义一个比较器即可。