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());
}

}