Java.io.StreamTokenizer.commentChar() 方法

描述

java.io.StreamTokenizer.commentChar(int ch) 方法指定字符参数启动一个单行注释。此流标记器忽略从注释字符到行尾的所有字符。清除指定字符的任何其他属性设置。

声明

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

 public int commentChar(int ch)

参数

ch - 字符。

返回值

此方法不返回值。

异常

N/a

例子

以下示例显示java.io.StreamTokenizer.commentChar()方法的用法。

 
package com.jc2182;

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);

         // set character "a" as a commentChar
         st.commentChar('a');

         // 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();
      }
   }
}

让我们编译并运行以上程序，这将产生以下结果-

 
< encountered.
Word: Hello.
Word: This
Word: is
End of File encountered.