集合排序 用Collections.sort(）

//年款分组HashSet h=new HashSet();
Set<Integer> yearSet=new HashSet<Integer>();
for(CarModelMongo model:carModelList){
yearSet.add(model.getYearName());
}
List<Integer> yearlist = new ArrayList(yearSet);
Collections.sort(yearlist,new CarModelYearComparator());
webForm.setYearlist(yearlist);

调用的比较器：

import java.util.Comparator;

public class CarModelYearComparator implements Comparator<Integer> {
@Override
public int compare(Integer o1, Integer o2) {
Integer model1 = (Integer)o1;
Integer model2 = (Integer)o2;
return model2.compareTo(model1);
}
}