java统计文件中字母出现的频率

import java.io.File;import java.io.BufferedReader;import java.io.FileReader;import java.io.IOException;public class a{public static void main(String args[]){File f=new File("1.txt");if(f.isFile()){try{BufferedReader b=new BufferedReader(new FileReader(f));StringBuffer sb=new StringBuffer();String t;while((t=b.readLine())!=null){sb.append(t+"/n");}String s=sb.toString();s.toLowerCase();char tj[]=s.toCharArray();int count[]=new int[26];for(int i=0; i<s.length(); i++){int j=tj[i]-'a';if(j>=0&&j<26){count[j]++;System.out.println(count[j]*1.0/(s.length()-1));}}}catch(IOException e){e.printStackTrace();}}}}