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.