统计字符串中大小写字符的个数（正则表达式做法）

package number;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class CountWords {


public static void main(String[] args) {
  InputStreamReader isr=new InputStreamReader(System.in);
  BufferedReader br=new BufferedReader(isr);
  System.out.println("请输入字符串：");
  String str="";
try {
str = br.readLine();
br.close();
} catch (IOException e) {

e.printStackTrace();
}
  Pattern p = Pattern.compile("[a-z]*");//小写字母
  Matcher m = p.matcher(str);
  StringBuffer lowercase = new StringBuffer();
  while(m.find()){
   lowercase.append(m.group(0));
  }
 
  p = Pattern.compile("[A-Z]*");//大写字母
  m = p.matcher(str);
  StringBuffer uppercase = new StringBuffer();
  while(m.find()){
   uppercase.append(m.group(0));
  }
 
  p = Pattern.compile("[^a-zA-Z]*");//非英文字母
  m = p.matcher(str);
  StringBuffer others = new StringBuffer();
  while(m.find()){
   others.append(m.group(0));
  }
  System.out.println("小写字母："+lowercase.length()+"个");
  System.out.println("大写字母："+uppercase.length()+"个");
  System.out.println("非英文字母："+others.length()+"个");


}

}