遍历两个字串实现加解密

比较好理解的一个方法

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            String strA = sc.next();
            String strB = sc.next();
            StringBuilder sb = new StringBuilder();
            for(int i = 0;i < strA.length();i++){
                char ch = strA.charAt(i);
                if(ch >= 48 && ch <= 57){   //0-9
                    if(ch == 57) sb.append(0);
                    else sb.append((char)(ch + 1));
                }else if(ch >= 65 && ch<= 90){   //A-Z
                    if(ch == 90) sb.append('a');
                    else sb.append((char)(ch + 33));
                }else if(ch >= 97 && ch <= 122){   //a-z
                    if(ch == 122) sb.append('A');
                    else sb.append((char)(ch - 31));
                }
            }
            strA = sb.toString();
            sb.setLength(0);
            for(int i = 0;i < strB.length();i++){
                char ch = strB.charAt(i);
                if(ch >= 48 && ch <= 57){   //0-9
                    if(ch == 48) sb.append('9');
                    else sb.append((char)(ch - 1));
                }else if(ch >= 65 && ch<= 90){   //A-Z
                    if(ch == 65) sb.append('z');
                    else sb.append((char)(ch + 31));
                }else if(ch >= 97 && ch <= 122){   //a-z
                    if(ch == 97) sb.append('Z');
                    else sb.append((char)(ch - 33));
                }
            }
            strB = sb.toString();
            sb.setLength(0);
            System.out.println(strA);
            System.out.println(strB);
         }
    }
}