java - 在字符串的最后，计算仅由唯一字符组成的字符串，忽略空字符串仅使用 Java StreamAPL

Question

在最后一个字符串中，计算仅由唯一字符组成的字符串，仅使用 Java StreamAPL 忽略空字符串我想我需要遍历 List 元素的符号并找到匹配项，但我不知道如何使用 Stream

`public static int scannerInt(){
         String inputInt = scannerString();
         int result;
         if (inputInt.matches("\\d+")){               //'''''''''''''''''''''''''
            result = Integer.parseInt(inputInt);      //Here we check whether the number is 
         }                                           //                             entered
         else {                                      // '''''''''''''''''''''''''
             System.out.println("You entered incorrect character.\nYou only need to enter 
     numbers!Try again : ");
             result = scannerInt();
         }
         return result;
     }

 //Here we just add elements to the List let it be "mom , eagle , brown , book , group".The 
 //result should be 3//(eagle,brown,group)

 enter code here`public static void countUniqueCharactersStream() {
         List<String> stringList = new ArrayList<>();
         Set<String> stringSet = new HashSet<>();
         int number = AllFunctions.scannerInt();
         for (int i = 0; i < number; i++) {
             stringList.add(AllFunctions.scannerString());
         }
     }`
     
     //I don't understand how to finish the code using Stream
     //I'm full