StreamTokenizer類nextToken()方法 (StreamTokenizer Class nextToken() method)

• nextToken() method is available in java.io package.

  nextToken()方法在java.io包中可用。

• nextToken() method is used to parse the next token from the input stream of this StreamTokenizer and the type of the next token is returned in the ttype field.

  nextToken()方法用于解析此StreamTokenizer的輸入流中的下一個標記，并且下一個標記的類型在ttype字段中返回。

• nextToken() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  nextToken()方法是一個非靜態方法，只能通過類對象訪問，如果嘗試使用類名稱訪問該方法，則會收到錯誤消息。

• nextToken() method may throw an exception at the time of returning next token.

  nextToken()方法在返回下一個令牌時可能會引發異常。

  IOException: This exception may throw when getting any input/output error while performing.

  IOException：在執行過程中遇到任何輸入/輸出錯誤時，可能引發此異常。

Syntax:

句法：

    Public int nextToken();

Parameter(s):

參數：

• It does not accept any parameter.

  它不接受任何參數。

Return value:

返回值：

The return type of the method is int, it gets the value of ttype field (i.e. type of the next token).

該方法的返回類型為int ，它獲取ttype字段的值(即下一個標記的類型)。

Example:

例：

// Java program to demonstrate the example 
// of int nextToken() method of StreamTokenizer
import java.io.*;
public class NextToken {
public static void main(String[] args) {
String str = "Hi, This is a mathematical expression : \n" +
" 2 * 4 = 8" + "8 + 5 = 13";
try {
// Instantiates FileOutputStream  and ObjectOutputStream 
FileOutputStream fos_stm = new FileOutputStream("D:\\includehelp.txt");
ObjectOutputStream obj_out_stm = new ObjectOutputStream(fos_stm);
// By using writeUTF() method is to
// write the given string in the file
obj_out_stm.writeUTF(str);
obj_out_stm.flush();
// Instantiates FileOutputStream  and ObjectOutputStream 
ObjectInputStream obj_in_stm = new ObjectInputStream(new FileInputStream("D:\\includehelp.txt"));
// Instantiates StreamTokenizer and Reader
Reader reader = new BufferedReader(new InputStreamReader(obj_in_stm));
StreamTokenizer st = new StreamTokenizer(reader);
// Here, we are considering initially 
// file is not empty
boolean end_of_file = false;
while (!end_of_file) {
// By using nextToken() method is to
// parse the next token from the stream
int token = st.nextToken();
switch (token) {
case StreamTokenizer.TT_EOF:
System.out.println("End of File Found");
end_of_file = true;
break;
case StreamTokenizer.TT_EOL:
System.out.println("End of Line Found");
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 + " Found.");
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
}

Output

輸出量

= Found.
word: Hi
, Found.
word: This
word: is
word: a
word: mathematical
word: expression
: Found.
number: 2.0
* Found.
number: 4.0
= Found.
number: 88.0
+ Found.
number: 5.0
= Found.
number: 13.0
End of File Found

翻譯自: https://www.includehelp.com/java/streamtokenizer-nexttoken-method-with-example.aspx