Java StreamTokenizer whitespaceChars（）方法及示例

StreamTokenizer类whitespaceChars()方法 (StreamTokenizer Class whitespaceChars() method)

whitespaceChars() method is available in java.io package.
whitespaceChars()方法在java.io包中可用。
whitespaceChars() method is used to denotes that all the characters lies in the given range(st[start], en[end]) are whitespace characters. Whitespace characters serve only to separate tokens in the input stream.
whitespaceChars()方法用于表示位于给定范围内的所有字符(st [start]，en [end])都是空白字符。空格字符仅用于分隔输入流中的标记。
whitespaceChars() method accepts two parameters and both parameters are of “int” type.
whitespaceChars()方法接受两个参数，并且两个参数均为“ int”类型。
whitespaceChars() method does not throw an exception at the time of representing whitespace characters.
表示空白字符时， whiteChars()方法不会引发异常。

Syntax:

句法：

    public void whitespaceChars(int st, int en);

Parameter(s):

参数：

int st – represents the starting endpoint of the given range.
int st –代表给定范围的起始端点。
int en – represents the ending endpoint of the given range.
int en –代表给定范围的终点。

Return value:

返回值：

The return type of the method is void, it returns nothing.

该方法的返回类型为void ，不返回任何内容。

Example:

例：

// Java program to demonstrate the example 
// of void whitespaceChars(int st, int en) method
// of StreamTokenizer
import java.io.*;
public class WhiteSpaceChars {
public static void main(String[] args) {
String str = "Hi, This is \n 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);
// By using whitespaceChars() method is to
// represent all the chars lies in between 
// (e,s) are whitespace chars
st.whitespaceChars('e', 's');
// 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

输出量

@ Found.
word: H
, Found.
word: T
word: a
word: at
word: at
word: ca
word: x
: Found.
number: 2.0
* Found.
number: 4.0
= Found.
number: 8.0
number: 8.0
+ Found.
number: 5.0
= Found.
number: 13.0
End of File Found