java-HJ36 字符串加密

import java.util.HashMap;
import java.util.HashSet;
import java.util.HashSet;
import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    private static final Integer SIZE = 26;
    private static final Integer LOWER_START = 97;
    private static final Integer UPPER_START = 65;

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        while (in.hasNext()){
            String key = in.nextLine();
            String word = in.nextLine();

            char[] keyChars = key.toCharArray();
            char[] wordChars = word.toCharArray();
            HashSet<Character> lowerKeyCharSet = new HashSet<>();
            HashSet<Character> upperKeyCharSet = new HashSet<>();
            HashMap<Character, Character> lowerKeyMap = new HashMap<>();
            HashMap<Character, Character> upperKeyMap = new HashMap<>();


            int lowerStart = LOWER_START;
            int upperStart = UPPER_START;
            for(char aChar: keyChars){
                if(Character.isUpperCase(aChar) && !upperKeyCharSet.contains(aChar)){
                    upperKeyCharSet.add(aChar);
                    upperKeyMap.put((char) upperStart++, aChar);
                }else if(Character.isLowerCase(aChar) && !lowerKeyCharSet.contains(aChar)){
                    lowerKeyCharSet.add(aChar);
                    lowerKeyMap.put((char) lowerStart++, aChar);
                }
            }

            for(int i=0; i<SIZE && upperStart<UPPER_START+SIZE; i++){
                Character upperChar = (char) (UPPER_START+i);

                if(!upperKeyCharSet.contains(upperChar)){
                    upperKeyCharSet.add(upperChar);
                    upperKeyMap.put((char) upperStart++, upperChar);
                }
            }

            for(int i=0; i<SIZE && lowerStart<LOWER_START+SIZE; i++){
                Character lowerChar = (char) (LOWER_START+i);

                if(!lowerKeyCharSet.contains(lowerChar)){
                    lowerKeyCharSet.add(lowerChar);
                    lowerKeyMap.put((char) lowerStart++, lowerChar);
                }
            }


            StringBuilder sb = new StringBuilder();
            for(char aChar: wordChars){
                if(Character.isUpperCase(aChar)){
                    sb.append(upperKeyMap.get(aChar));
                }else if(Character.isLowerCase(aChar)){
                    sb.append(lowerKeyMap.get(aChar));
                }
            }

            System.out.println(sb);
         }
    }
}