程序计算输入单词的次数，然后按降序返回单词和使用次数

Question

目的是创建一个程序，该程序将计算单词的输入次数，同时忽略大小写和标点符号，然后将单词及其输入次数按降序返回到控制台。目前，我的程序统计字母数并将其返回到控制台，但它不会忽略大小写或标点符号。我也不知道如何添加排序函数。谢谢你的时间/帮助。

编辑：不确定原始代码发生了什么变化，但当我上次在eclipse中运行它时，计数器忽略了标点符号和大小写。然而，计数器仍然在跟踪字母而不是单词。

public static void main(String[] args) {
    String txt = readText();
    String[] words = txtToWords(normalize(txt));
    HashMap<String, Integer> wordCount = countWords(words);
    //Print to console how many times each word was entered 
    System.out.println(txt + "was found" + wordCount + "times");
}
    //Increases word counter by 1 each time a duplicate word is entered
public static HashMap<String, Integer> countWords(String[] words) {
    HashMap<String, Integer> wordCount = new HashMap<String, Integer>();
    for (String word : words) {
        if (wordCount.containsKey(word)) {
            int count = wordCount.get(word);
            count = count + 1;
            wordCount.put(word, count);
        } else {
            wordCount.put(word, 1);
        }
    }
    return wordCount;
}
public static String[] txtToWords(String txt) {
    return txt.split("");
}
    //Removes punctuation and ignores case when counting
public static String normalize(String txt) {
    txt = txt.replaceAll("[^a-zA-Z ]", "").toLowerCase();
    return txt;
}
    //Reads the text entered by the user
public static String readText() {
    System.out.println("Please enter the text to be processed.");
    String stop = "*** LAST LINE ***";
    System.out.println("Enter: "" + stop + "" to stop");
    StringBuilder results = new StringBuilder();
    Scanner input = new Scanner(System.in);
    while (true) {
        String line = input.nextLine();
        if (line.contains(stop)) {
            break;
        } else {
            results.append(line);
        }
    }
    return results.toString().trim();
}

}

Answer 1

因为使用normalize方法在字符串中留下了空格。你应该拆分这些而不是一个空字符串：

str.split("\s+");