wordcount.java

输入输出程序演示例子

/*
******************************
* File Name: Counter.java
* Author:wangch
* Function Description:counter class 
*
*****************************
*/
package com.io;
import java.util.*;
import java.io.*;

 class Counter
{
  private int i = 1;
  int read() { return i;}
  void increment() { i++;}
}

 class WordCount {
  private FileReader file;
  private StreamTokenizer st;
  //A TreeMap keeps keys in sorted order:
  private TreeMap count = new TreeMap();
  WordCount(String fileName)
    throws FileNotFoundException {
    try{
      
      file = new FileReader(fileName);
      st = new StreamTokenizer(
            new BufferedReader(file));
      countWords(); 
    } catch(FileNotFoundException e) {
      System.out.println(
      "Cound not open " + fileName);
      throw e;
      }
  }

void clearup() {
  try{
    file.close();
  } catch (IOException e) {
    System.out.println(
      "file.close() unsuccessful");
  }
}
void countWords() {
  try{
    while(st.nextToken()!=
      StreamTokenizer.TT_EOF) {
      String s;
      switch(st.ttype) {
        case StreamTokenizer.TT_EOF :
          s = new String("EOL");
          break;
        case StreamTokenizer.TT_NUMBER :
          s = Double.toString(st.nval);
          break;
         case StreamTokenizer.TT_WORD :
           s = st.sval;
         break;
         default:
           s= String.valueOf((char)st.ttype);
      }
      if(count.containsKey(s))
        ((Counter)count.get(s)).increment();
      else
        count.put(s,new Counter());
    }//end of while
  }catch(IOException e) {
    System.err.println( "st.nextToken() unsuccessful");
 }
}
Collection values() {
  return count.values();
}
Set keySet() { return count.keySet();}

Counter getCounter(String s) {
  return (Counter)count.get(s);
}

public static void main(String [] args)
  throws FileNotFoundException {
  WordCount wc =
    new WordCount(args[0]);
  Iterator keys =wc.keySet().iterator();
  while(keys.hasNext()) {
    String key = (String)keys.next();
    System.out.println(key + ":" +wc.getCounter(key).read());
  }
  wc.clearup();
 }
}