统计英文字母出现次数

源码：

package yingwen;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
public class yingwen {
 private int num[]=new int[52];
 public void readTxt(String filePath) {

  try {
   File file = new File(filePath);
   if(file.isFile() && file.exists()) {
    InputStreamReader isr = new InputStreamReader(new FileInputStream(file), "utf-8");
    while(isr.ready())
    {
     char c=(char)isr.read();
     if(c>='a'&&c<='z')
     {
      ++num[(int)(c-'a')];
     }
     else if(c>='A'&&c<='Z')
     {
      ++num[(int)(c-'A')];
     }
    }
    //         BufferedReader br = new BufferedReader(isr);
    //         String lineTxt = null;
    //         while ((lineTxt = br.readLine()) != null) {
    //           System.out.println(lineTxt);
    //         }
    //         br.close();
    isr.close();
   } else {
    System.out.println("文件不存在!");
   }
  } catch (Exception e) {
   System.out.println("文件读取错误!");
  }

 }
 public int[] num1()
 {
  return num;
 }

 public static void main(String[] args) {
  String filePath = "E:\Yingwen\English.txt";
  yingwen a=new yingwen();
  a.readTxt(filePath);
  int num[]=a.num1();
  for(int i=0;i<52;i++)
  {
   if(i<=25)
    System.out.println((char)(i+'a')+" "+num[i]);
   else System.out.println((char)(i+'A'-26)+" "+num[i]);
  }
 }
}