JAVA统计文件中每个单词出现的数量

package demo;

import java.io.*;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author yeqv
 * @program A2
 * @Classname A3
 * @Date 2022/1/19 20:55
 * @Email w16638771062@163.com
 */
public class A3 {

    public static void main(String[] args) {
        Set<String> set = new HashSet<>();
        List<String> list = new ArrayList<>();
        File file = new File("D:\\jdk.txt");
        Pattern pattern = Pattern.compile("\s[a-zA-Z]+\s");
        String len;
        try {
            BufferedReader buff = new BufferedReader(new FileReader(file));
            while ((len = buff.readLine()) != null) {
                Matcher matcher = pattern.matcher(len);
                while (matcher.find()) {
                    set.add(matcher.group());
                    list.add(matcher.group());
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        int b = 1;
        for (String s : set) {
            int a = 0;
            for (String s1 : list) {
                if (s.equals(s1)) {
                    a += 1;
                }
            }
            System.out.printf("%d单词：%s 数量：%d%n", b, s, a);
            b += 1;
        }

    }

}