检查文件是否包含字符串，并为新字符串创建数组

Question

我需要创建一个方法来读取文件，并检查文件中的每个单词。文件中的每个新词都应该存储在字符串数组中。该方法应该不区分大小写。请帮帮忙。

该文件写道:不要问你的国家能为你做什么，你要问你能为你的国家做什么

所以数组应该只包含: ask，not，what，your，country，can，do，for，you

import java.util.*;
import java.io.*;

public class TextAnalysis {

public static void main (String [] args) throws IOException {
    File in01 = new File("a5_testfiles/in01.txt");
    Scanner fileScanner = new Scanner(in01);

    System.out.println("TEXT FILE STATISTICS");
    System.out.println("--------------------");
    System.out.println("Length of the longest word: " + longestWord(fileScanner));
    System.out.println("Number of words in file wordlist: " );
    countWords();
    System.out.println("Word-frequency statistics");

}

public static String longestWord (Scanner s) {
    String longest = "";
    while (s.hasNext()) {
        String word = s.next();
        if (word.length() > longest.length()) {
            longest = word;
        }
    }

    return (longest.length() + " " + "(\"" + longest + "\")");
}

public static void countWords () throws IOException {
    File in01 = new File("a5_testfiles/in01.txt");
    Scanner fileScanner = new Scanner(in01);  
    int count = 0;

        while(fileScanner.hasNext()) {
            String word = fileScanner.next();
                count++;
        }

    System.out.println("Number of words in file: " + count);
}

public static int wordList (int words) {
    File in01 = new File("a5_testfiles/in01.txt");
    Scanner fileScanner = new Scanner(in01); 

    int size = words;
    String [] list = new String[size];

    for (int i = 0; i <= size; i++) {

        while(fileScanner.hasNext()){
            if(!list[].contains(fileScanner.next())){
                list[i] = fileScanner.next();
            }
        }
    }
}

}

Answer 1

你可以试着：

List<String> words = new ArrayList<String>();

//read lines in your file all at once
List<String> allLines = Files.readAllLines(yourFile, Charset.forName("UTF-8"));

for(int i = 0; i < allLines.size(); i++) {

    //change each line from your file to an array of words using "split(" ")".
    //Then add all those words to the list "words"
    words.addAll(Arrays.asList(allLines.get(i).split(" ")));

}

//convert the list of words to an array.
String[] arr = words.toArray(new String[words.size()]);

使用Files.readAllLines(yourFile, Charset.forName("UTF-8"));读取yourFile的所有行要比单独读取每一行要干净得多。你的方法的问题是你计算的是行数，而不是字数。如果一行中有多个单词，则输出将不正确。

或者，如果您不使用Java7，您可以创建一个行列表，如下所示，然后计算末尾的单词数(与countWords()中的方法相反

List<String> allLines = new ArrayList<String>();

Scanner fileScanner = new Scanner(yourFile);
while (fileScanner.hasNextLine()) {
     allLines.add(scanner.nextLine());    
}

fileScanner.close();

然后，如前面的代码所示，拆分每一行并创建数组。还要注意，理想情况下，您应该在扫描仪周围使用try{} catch块，而不是throws。

Answer 2

你可以利用我下面的代码片段(它不会存储重复的单词)！

File file = new File("names.txt");

FileReader fr = new FileReader(file);
StringBuilder sb = new StringBuilder();
char[] c = new char[256];
while(fr.read(c) > 0){
    sb.append(c);
}


String[] ss = sb.toString().toLowerCase().trim().split(" ");
TreeSet<String> ts = new TreeSet<String>();

for(String s : ss)
    ts.add(s);

for(String s : ts){
    System.out.println(s);
}

输出结果为：

ask
can
country
do
for
not
what
you
your