Question

我正在进行一项使用带有lambda语法的Java流的作业。该程序应该被设计（1）计算一组文件（2）计算这些文件中的单词（3）打印并显示结果。这是输出的一个例子：

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

但是，我得到的是这个输出：

primes.txt
word length: 1 ==> hw8.WordCount@5c647e05
constitution.txt
word length: 2 ==> hw8.WordCount@33909752
short.txt
word length: 3 ==> hw8.WordCount@55f96302
.....
Count: 11 files

我写的程序分为两个类 - FileCatch，它计算文件，WordCount计算单词（理论上）。如果有人有任何编程技巧可以提供帮助，我将不胜感激。

FileCatch班

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;
            for (Path path : directoryStream) {
                System.out.println(path.getFileName());
                fileCounter++;
                fileNames.add(path.getFileName().toString());
                WordCount WordCnt = new WordCount();
                System.out.println("word length: " +  fileCounter + " ==> " + WordCnt);
            }
    }catch(IOException ex){
    }
    System.out.println("Count: "+fileNames.size()+ " files");

  }
}

WordCount类：

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

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

    /**
     *
     * @return 
     * @throws IOException
     */
    public Map<String, Long> WordCount()throws IOException {
        Stream<String> lines = Files.lines(Paths.get("constitution.txt"));
        Map<String, Long> wordMap = lines
                .parallel()
                .map(String::toLowerCase)
                .map(line -> line.split("\\W+"))
                .flatMap(line -> Arrays.asList(line).stream())
                .filter(word -> !word.matches("\\d+") && word.trim().length() != 0)
                .map(word -> new SimpleEntry<>(word, 1))
                .collect(groupingBy(SimpleEntry::getKey, counting()));
        new TreeMap(wordMap).forEach((k, v) -> 
                System.out.println(String.format("%s word length: 1 ==> %d", k, v)));
        return wordMap;
    }
}

Answer 1

您正在打印WordCount课程的实例，这没有任何意义。您也永远不会调用WordCount()方法。

您应该创建WordCount的单个实例，并调用为每个文件执行单词计数的方法（我重命名了一些方法和变量以使代码更具可读性）：

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()));
}


public class WordCount {

    /**
     *
     * @return 
     * @throws IOException
     */
    public Map<String, Long> count(String filename) throws IOException {
        Stream<String> lines = Files.lines(Paths.get(filename));
        Map<String, Long> wordMap = lines
                .parallel()
                .map(String::toLowerCase)
                .map(line -> line.split("\\W+"))
                .flatMap(line -> Arrays.asList(line).stream())
                .filter(word -> !word.matches("\\d+") && word.trim().length() != 0)
                .map(word -> new SimpleEntry<>(word, 1))
                .collect(groupingBy(SimpleEntry::getKey, counting()));
        new TreeMap(wordMap).forEach((k, v) -> 
                System.out.println(String.format("%s word length: 1 ==> %d", k, v)));
        return wordMap;
    }
}

请注意，您的WordCount类似乎计算文件中每个单词的外观，而不是文件中单词的总数，因此它似乎与您在开始时发布的预期输出不匹配你的问题。

来自java 8文件/单词计数程序的奇怪输出

1 个答案: