1 package jihe; 2  3 import java.util.*; 4  5 public class Test { 6      7     public static void main(String[] args) 8     { 9         //创建set类的实例10         Set
     
       set = new TreeSet<>();11         12         //添加元素13         set.add("A");14         set.add("a");15         set.add("c");16         set.add("C");17         set.add("a");18         19         //遍历集合20         for(String x : set)21         {22             System.out.println("set = " + x);23         }24         25         26         27         28         29         //创建List类的实例30         List
      
        list = new ArrayList<>();31         32         //添加元素33         list.add("A");34         list.add("a");35         list.add("c");36         list.add("C");37         list.add("a");38         39         //遍历集合40         for(String x : list)41         {42             System.out.println("list = " + x);43         }44         45         46     }47 48 }
      
     

运行结果

set = A

set = C

set = a

set = c

list = A

list = a

list = c

list = C

list = a