Java I/O - 如何通过StringReader从字符串读取

import java.io.StreamTokenizer;
import java.io.StringReader;

public class Main {
  public static void main(String[] args) throws Exception{
    StringReader reader = new StringReader("this is a test");

    int wordCount = 0;
    StreamTokenizer streamTokenizer = new StreamTokenizer(reader);

    while (streamTokenizer.nextToken() != StreamTokenizer.TT_EOF) {
      if (streamTokenizer.ttype == StreamTokenizer.TT_WORD)
        wordCount++;
    }
    System.out.println("Number of words in file: " + wordCount);
  }
}