问Java中的拼写检查器，文件打开但无输出

EN

import java.io.*;
import java.util.Scanner;
import java.util.HashSet;
import javax.swing.*;
import java.util.TreeSet;

/**
 * This class works as a basic spell-checker. It uses the file words.txt to
 * check whether a given word is correctly spelled.
 */
public class SpellChecker {

    public static void main(String[] args) {

        Scanner words;
        HashSet<String> dict = new HashSet<String>();
        Scanner userFile;

        try {

            words = new Scanner(new File("src/words.txt"));

            while (words.hasNext()) {
                String word = words.next();
                dict.add(word.toLowerCase());
            }

            userFile = new Scanner(getInputFileNameFromUser());

            // Skip over any non-letter characters in the file.
            userFile.useDelimiter("[^a-zA-Z]+");

            HashSet<String> badWords = new HashSet<String>();
            while (userFile.hasNext()) {
                String userWord = userFile.next();
                userWord = userWord.toLowerCase();
                if (!dict.contains(userWord) && 
                    !badWords.contains(userWord)) {

                    badWords.add(userWord);
                    TreeSet<String> goodWords = new TreeSet<String>();
                    goodWords = corrections(userWord, dict);
                    System.out.print(userWord + ": ");
                    if (goodWords.isEmpty())
                        System.out.println("(no suggestions)");
                    else {
                        int count = 0;
                        for (String goodWord: goodWords) {
                            System.out.print(goodWord);
                            if (count < goodWords.size() - 1)
                                System.out.print(", ");
                            else
                                System.out.print("\n");
                            count++;
                        }
                    }

                }

            }

        }
        catch (FileNotFoundException e) {
            System.exit(0);
        }

    } // end main()

    /**
     * Lets the user select an input file using a standard file selection
     * dialog box. If the user cancels the dialog without selecting a file,
     * the return value is null.
     *
     * @return A file selected by the user, if any. Otherwise, null.
     */
    static File getInputFileNameFromUser() {

        JFileChooser fileDialog = new JFileChooser();
        fileDialog.setDialogTitle("Select File for Input");
        int option = fileDialog.showOpenDialog(null);
        if (option != JFileChooser.APPROVE_OPTION)
            return null;
        else
            return fileDialog.getSelectedFile();

    } // end getInputFileNameFromUser()

    /*
     * Gives a list of possible correct spellings for misspelled words which
     * are variations of a a given word that are present in the dictionary.
     *
     * @return A tree set containing a list of possible corrections to the
     *         misspelled word.
     */
    static TreeSet<String> corrections(String badWord, HashSet<String> dictionary) {

        TreeSet<String> possibleWords =  new TreeSet<String>();
        String subStr1, subStr2, possibility;

        for (int i = 0; i < badWord.length(); i++) {

            // Remove character i from the word.
            subStr1 = badWord.substring(0, i);
            subStr2 = badWord.substring(i + 1);

            // Delete any one of the letters from the misspelled word.
            possibility = subStr1 + subStr2;
            if (dictionary.contains(possibility))
                possibleWords.add(possibility);

            // Change any letter in the misspelled word into any other
            // letter.    
            for (char ch = 'a'; ch <= 'z'; ch++) {
                possibility = subStr1 + ch + subStr2;
                if (dictionary.contains(possibility))
                    possibleWords.add(possibility);
            }

            // Divide the word into two substrings.
            subStr1 = badWord.substring(0, i);
            subStr2 = badWord.substring(i);

            // Insert any letter at any point in the misspelled word.
            for (char ch = 'a'; ch <= 'z'; ch++) {
                possibility = subStr1 + ch + subStr2;
                if (dictionary.contains(possibility))
                    possibleWords.add(possibility);
            }

            // Insert a space at any point in the misspelled word and check
            // that both of the words that are produced are in the dictionary.
            char ch = ' ';
            possibility = subStr1 + ch + subStr2;
            if (dictionary.contains(subStr1) && dictionary.contains(subStr2))
                      possibleWords.add(possibility);

        }

        // Swap any two neighbouring characters in the misspelled word.
        for (int i = 1; i < badWord.length(); i++) {
            subStr1 = badWord.substring(0, i - 1);
            char ch1 = badWord.charAt(i - 1);
            char ch2 = badWord.charAt(i);
            subStr2 = badWord.substring(i + 1);
            possibility = subStr1 + ch2 + ch1 + subStr2;
            if (dictionary.contains(possibility))
                possibleWords.add(possibility);
        }

        return possibleWords;

    } // end corrections()

} // end class SpellChecker