java 排序

class User {
 public Integer age;

 public Integer getAge() {
  return age;
 }

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

 public User(Integer age) {
  this.age = age;
 }
}

import java.util.Comparator;

public class ComparatorUser implements Comparator {

 public int compare(Object arg0, Object arg1) {
  User user0=(User)arg0;
  User user1=(User)arg1;


  return  user0.getAge().compareTo(user1.getAge());




 }
 
}

    public static void main(String[] args) {
        List userlist = new ArrayList();
        userlist.add(new User(4));
        userlist.add(new User(1));
        userlist.add(new User(3));
        userlist.add(new User(0));
        userlist.add(new User(5));
        userlist.add(new User(5));

        ComparatorUser comparator = new ComparatorUser();
        Collections.sort(userlist, comparator);

        for (int i = 0; i < userlist.size(); i++) {
            User user_temp = (User) userlist.get(i);
            System.out.println(user_temp.getAge());
        }

    }