filewordreader.java

统计文件内不同文字出现的频率

package eclipse.workspace.Word.src;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.StreamTokenizer;

/**
 * A class to read words from a file, one word at a time.
 * Personal note: I do not like the StreamTokenizer class used below as it is unwieldy and inelegant.
 * However, it is very expedient in this example.
 * 
 * @author Justin Templemore-Finlayson, ECE
 * 
 */
public class FileWordReader 
{
	private StreamTokenizer stream;
	private long wordCount;
	
	/**
	 * Creates an FileWordReader object that reads one word at a time from the specified text file.
	 * The text file must be located in the current working directory (in eclipse, this is the root
	 * directory of the project).
	 * @param fileName
	 * @throws FileNotFoundException
	 */
	public FileWordReader (String fileName) throws FileNotFoundException
	{
		stream = new StreamTokenizer (new FileReader(new File (fileName)));	// looks for character file in current dir
		wordCount = 0;
	}
	/**
	 * Gets the next word from the file.
	 * If there are no more words, the method returns a null.
	 * @return The next word.
	 */
	public String getNextWord()
	{
		String word = null;
		int tokenType;
	    do {
	        try 
	        {
				tokenType = stream.nextToken ();
		        if (tokenType == StreamTokenizer.TT_WORD) 
		        {
		        	word = stream.sval;
		        	wordCount++;
		        }
			} 
	        catch (IOException e) 
	        {
	        	word = null;
	        	break;
			} 
	      } 
	    while (tokenType != StreamTokenizer.TT_EOF && word == null);
	    return word;
	}
	/**
	 * Returns the number of words counted by this object.
	 * @return The number of words counted so far
	 */
	public long getWordCount() 
	{
		return wordCount;
	}
	/**
	 * Short program to test my method
	 * @param args
	 */
	public static void main(String[] args) 
	{
		FileWordReader fwr;
		try 
		{
			fwr = new FileWordReader ("story.txt");
			System.out.println ("OK! File found!");
			String word = fwr.getNextWord();
			while (word != null)
			{
				System.out.println ("* " + word);
				word = fwr.getNextWord();
			}
			System.out.println ("Finished reading. There were " + fwr.getWordCount() + " words.");
		} catch (FileNotFoundException e) 
		{
			System.out.println ("KO! File not found!");
		}
		
	}
}