从控制台获取一串字符串，并对每个字符出现的次数进行统计

 /*
 * 从控制台获取一串字符串，并对每个字符出现的次数进行统计
 */

package test3_21;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *
 * @author dnktty
 */

class AccountChar {

    public static int n=1;

    public static void main(String[] args){
   
        //建立输入流，从用户获取需要统计的字符串
        BufferedReader buffR=new  BufferedReader(
                                      new InputStreamReader(System.in));

        try {

             System.out.println("请输入一串需要统计的字符串：");
             String str = buffR.readLine();

            AccountChar ac=new AccountChar();
            //对统计的字符串拆成字符
            char[] ch=str.toCharArray();

             for(int i=0;i                if(str.indexOf(ch[i])==i)  //排除重复出现的字符
                System.out.println(ch[i] +" the number is "+ac.accountNumber(str,i));
                n=1;  //恢复全局变量的值
            }//end for loop

        }//end try
        catch (IOException ex) {  ex.printStackTrace(); }

    }

    //用递归方法统计字符串中某个元素的个数  a为元素在str中的索引值
    public int accountNumber(String str,int a){
         int b=a;
       
         a=a+1;
         String subStr=str.substring(a,str.length());
      
         if(subStr.indexOf(str.charAt(b))!=-1){
             n++;
             return accountNumber(subStr,subStr.indexOf(str.charAt(b)));
             // return accountNumber(subStr,b);//会重复算vabsa 算a时会在b和s出各算一次

         }
         return n;

    }

}