升序 Collections.sort(list) 降序 Collections.reserve(list) 随机 Collections.shuffle(list)

package Day28ketangzuoye; import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner; public class DemoChars{ public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("请输入N个字符：");
String str=sc.next();
String[] arr=str.split(",");
// System.out.println(Arrays.toString(arr)); List<String> list=new ArrayList<String>();
for(int i=0;i<arr.length;i++){
list.add(arr[i]);
}
System.out.println("原序输出： "+list); Collections.sort(list);
System.out.println("升序输出： "+list); Collections.sort(list,new Comparator<String>(){
@Override
public int compare(String o1, String o2) {
return o2.compareTo(o1);
}});
System.out.println("降序输出： "+list); Collections.reverse(list);
System.out.println("反转指定列表中元素的顺序 "+list); // Set set = new ArraySet(list);
// HashSet<String> set=new HashSet<String>(list);
// System.out.println("无序输出： "+set);
// 升序 Collections.sort(list) 降序 Collections.reserve(list) 随机 Collections.shuffle(list) }
}