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Java.io.StreamTokenizer.parseNumbers()方法实例

java.io.StreamTokenizer.parseNumbers() 方法指定数字应该由这个标记生成器解析。标记生成器的语法表被修改,使得每个12个字符的:0 1 23 4 5 67 8 9。 - 具有“数字”属性。

声明

以下是java.io.StreamTokenizer.parseNumbers()方法的声明

public void parseNumbers()

参数

  • NA

返回值

这个方法没有返回值

异常

  • NA

例子

下面的例子显示java.io.StreamTokenizer.parseNumbers()方法的用法。

package com.yiibai;

import java.io.*;

public class StreamTokenizerDemo {

   public static void main(String[] args) {

      String text = "Hello. This is a text 
 that will be split "
              + "into tokens. 1+1=2";
      try {
         // create a new file with an ObjectOutputStream
         FileOutputStream out = new FileOutputStream("test.txt");
         ObjectOutputStream oout = new ObjectOutputStream(out);

         // write something in the file
         oout.writeUTF(text);
         oout.flush();

         // create an ObjectInputStream for the file we created before
         ObjectInputStream ois =
                 new ObjectInputStream(new FileInputStream("test.txt"));

         // create a new tokenizer
         Reader r = new BufferedReader(new InputStreamReader(ois));
         StreamTokenizer st = new StreamTokenizer(r);

         // specify that numbers should be parsed
         st.parseNumbers();

         // print the stream tokens
         boolean eof = false;
         do {

            int token = st.nextToken();
            switch (token) {
               case StreamTokenizer.TT_EOF:
                  System.out.println("End of File encountered.");
                  eof = true;
                  break;
               case StreamTokenizer.TT_EOL:
                  System.out.println("End of Line encountered.");
                  break;
               case StreamTokenizer.TT_WORD:
                  System.out.println("Word: " + st.sval);
                  break;
               case StreamTokenizer.TT_NUMBER:
                  System.out.println("Number: " + st.nval);
                  break;
               default:
                  System.out.println((char) token + " encountered.");
                  if (token == '!') {
                     eof = true;
                  }
            }
         } while (!eof);


      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
}

让我们编译和运行上面的程序,这将产生以下结果:

Word: Hello.
Word: This
Word: is
Word: a
Word: text
Word: that
Word: will
Word: be
Word: split
Word: into
Word: tokens.
Number: 1.0
+ encountered.
Number: 1.0
= encountered.
Number: 2.0
End of File encountered.