Java implementiert das Zählen der Anzahl verschiedener Zeichen oder Zahlen in einer Zeichenfolge

package com.one;
import java.util.*;
public class Flqgs {
	public static Scanner input = new Scanner(System.in);
	public static void main(String[] args) {
		System.out.println("请输入一行字符串：");
		String num = input.nextLine();
		int digital = 0, character = 0, other = 0, blank = 0;
		char [] ch = num.toCharArray();
		
		for(int i=0;i<ch.length;i++){
			if(ch[i] >= &#39;a&#39; && ch[i] <= &#39;z&#39; || ch[i] >= &#39;A&#39; && ch[i] <= &#39;z&#39;){
				character++;
			}else if(ch[i] >= &#39;0&#39; && ch[i] <= &#39;9&#39;){
				digital++;
			}else if(ch[i] == &#39; &#39;){
				blank++;
			}else{
				other++;
			}
		}
		System.out.println("字母个数："+character);
		System.out.println("数字个数："+digital);
		System.out.println("空格个数："+blank);
		System.out.println("其他个数："+other);
	}
}