我想从用户输入字符串，其中只有字母，点（.）和空间是允许的。如果用户输入除这些字符以外的任何其他字符，我的程序应该再次从用户那里获取输入。它应该继续这个过程，直到用户输入正确的输入（这是我想要的）。在任何时候，如果用户输入右键，它会移动得更远。我试过给定的代码，但不起作用。

import java.util.Scanner;
public class TourPlanner{
    public static boolean validname(String name){
        String nameUp=name.toUpperCase();
        for(int i=0;i<nameUp.length();i++){
            char charUp=nameUp.charAt(i);
                if(charUp=='A' || charUp=='B' || charUp=='C' || charUp=='D' || charUp=='E' || charUp=='F' || charUp=='G' || charUp=='H' || charUp=='I' || charUp=='J' || charUp=='K' || charUp=='L' || charUp=='M' || charUp=='N' || charUp=='O' || charUp=='P' || charUp=='Q' || charUp=='R' || charUp=='S' || charUp=='T' || charUp=='U' || charUp=='V' || charUp=='W' || charUp=='X' || charUp=='Y' || charUp=='Z' || charUp=='.' || charUp==' '){
                return true;
            }
        }
        return false;
    }//valid name
    public static void intro(String name, Scanner in){
        validname(name);
        while(validname(name)==false){
            System.out.print("***Please Enter Name Correctly***\n");
            System.out.print("What is your Name? ");
            name=in.nextLine();
        }
        String designation;
        System.out.print("Nice to meet you "+name+" Where are you travelling to? ");
        designation=in.nextLine();
        System.out.print("Great! "+designation+" sounds like a great trip.");
    }//intro
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        System.out.println("****Welcome to tour Planner****\n");
        System.out.print("What is your Name?");
        String name=in.nextLine();
        intro(name,in);
        System.out.println("\n\n********************************************\n");
    }//main
}