[abcde, cba, aa, zzz, cba, nbaa]

[aa, cba, cba, zzz, nbaa, abcde]

package zhouls.bigdata.DataFeatureSelection.test;import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.TreeSet;import zhouls.bigdata.DataFeatureSelection.test.ComparatorByLength;public class CollectionsDemo {/*** @param args*/public static void main(String[] args) {/** Collections：是集合框架的工具类。* 里面的方法都是静态的。*/demo();}public static void demo(){List<String> list = new ArrayList<String>();list.add("abcde");list.add("cba");list.add("aa");list.add("zzz");list.add("cba");list.add("nbaa");System.out.println(list);//对list集合进行指定顺序的排序。
        Collections.sort(list);mySort(list);mySort(list,new ComparatorByLength());Collections.sort(list,new ComparatorByLength());System.out.println(list);}public static <T> void mySort(List<T> list,Comparator<? super T> comp){for (int i = 0; i < list.size()-1; i++) {for (int j = i+1; j < list.size(); j++) {if(comp.compare(list.get(i), list.get(j))>0){T temp = list.get(i);list.set(i, list.get(j));list.set(j, temp);Collections.swap(list, i, j);}}}}public static <T extends Comparable<? super T>> void mySort(List<T> list){for (int i = 0; i < list.size()-1; i++) {for (int j = i+1; j < list.size(); j++) {if(list.get(i).compareTo(list.get(j))>0){
//                    T temp = list.get(i);
//                    list.set(i, list.get(j));
//                    list.set(j, temp);
                    Collections.swap(list, i, j);}}}}
}

package zhouls.bigdata.DataFeatureSelection.test;import java.util.Comparator;public class ComparatorByLength implements Comparator<String> {public int compare(String o1, String o2) {int temp = o1.length() - o2.length();return temp==0?o1.compareTo(o2): temp;}
}