lambda如何计算文本文件中的字数，java 8style

Question

我正在尝试执行一个赋值，该赋值首先计算目录中的文件数，然后给出每个文件中的字数。我得到了文件数，但我很难将我的老师给我的一些代码从一个进行频率计数的类转换为更简单的单词计数。此外，我似乎找不到正确的代码来查看每个文件以计算单词（我试图找到“通用”而不是特定的代码，但我试图使用特定的文本文件测试程序）。这是预期输出：

Count 11 files:
word length: 1 ==> 80
word length: 2 ==> 321
word length: 3 ==> 643

但是，这是正在输出的内容：

primes.txt
but
are
sometimes
sense
refrigerator
make
haiku
dont
they
funny
word length: 1 ==> {but=1, are=1, sometimes=1, sense=1, refrigerator=1, make=1, haiku=1, dont=1, they=1, funny=1}

.....

Count 11 files:

我使用两个类：WordCount和FileCatch8

字数：

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.AbstractMap.SimpleEntry;
import java.util.Arrays;
import java.util.Map;
import static java.util.stream.Collectors.counting;
import static java.util.stream.Collectors.groupingBy;

    /**
     *
     * @author 
     */
    public class WordCount {

        /**
         *
         * @param filename
         * @return
         * @throws java.io.IOException
         */
        public Map<String, Long> count(String filename) throws IOException {
            //Stream<String> lines = Files.lines(Paths.get(filename));
            Path path = Paths.get("haiku.txt");
            Map<String, Long> wordMap = Files.lines(path)
                    .parallel()
                    .flatMap(line -> Arrays.stream(line.trim().split(" ")))
                    .map(word -> word.replaceAll("[^a-zA-Z]", "").toLowerCase().trim())
                    .filter(word -> word.length() > 0)
                    .map(word -> new SimpleEntry<>(word, 1))
                    //.collect(Collectors.toMap(s -> s, s -> 1, Integer::sum));
                    .collect(groupingBy(SimpleEntry::getKey, counting()));

            wordMap.forEach((k, v) -> System.out.println(String.format(k,v)));
            return wordMap;
        }
    }

和文件捕获：

import java.io.IOException;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author 
 */
public class FileCatch8 {
    public static void main(String args[]) {
        List<String> fileNames = new ArrayList<>();
        try {
            DirectoryStream<Path> directoryStream = Files.newDirectoryStream
        (Paths.get("files"));
            int fileCounter = 0;
            WordCount wordCnt = new WordCount();
            for (Path path : directoryStream) {
                System.out.println(path.getFileName());
                fileCounter++;
                fileNames.add(path.getFileName().toString()); 
                System.out.println("word length: " +  fileCounter + " ==> " + 
                        wordCnt.count(path.getFileName().toString()));
}
        } catch(IOException ex){
    }
    System.out.println("Count: "+fileNames.size()+ " files");

  }
}

该程序使用带有lambda语法的Java8流

Answer 1

在我看来，使用Java 8计算文件中单词的最简单方法是：

Long wordsCount = Files.lines(Paths.get(file))
    .flatMap(str->Stream.of(str.split("[ ,.!?\r\n]")))
    .filter(s->s.length()>0).count();
System.out.println(wordsCount);

要清点所有文件，请执行以下操作：

Long filesCount = Files.walk(Paths.get(file)).count();
System.out.println(filesCount);

Answer 2

字数统计示例：

Files.lines(Paths.get(file))
    .flatMap(line -> Arrays.stream(line.trim().split(" ")))
    .map(word -> word.replaceAll("[^a-zA-Z]", "").toLowerCase().trim())
    .filter(word -> !word.isEmpty())
    .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

文件计数：

Files.walk(Paths.get(file), Integer.MAX_VALUE).count();
Files.walk(Paths.get(file)).count();