Unicode and ASCII

How can you read and write unicode? Ascii?

Java employs Unicode in the following sense:

• The "char" data type is defined to be a Unicode type.
• Strings, since they are composed of char data, are therefore also Unicode-based.
• Java identifiers can contain Unicode characters. You can specify Unicode characters using the \u escape sequence.

Thus, if you read and write data using the typed methods in the DataInputStream and DataOutputStream classes, you will be able to store and retrieve Unicode data (and other Java data types as well).

To write Ascii data you may use the FileOutputStream.writeChars() and DataOutputStream.writeBytes() methods (and similar methods for reading). Note that to create a DataOutputStream, you must first create a FileOutputStream, and then construct the DataOutputStream from that.

// write unicode data as unicode
FileOutputStream ufos = new FileOutputStream("test.ucd");
DataOutputStream udos = new DataOutputStream(ufos);
udos.writeChars("ABCDE");	// writes Unicode
udos.close();

// write unicode data as ascii
FileOutputStream xfos = new FileOutputStream("test.xxx");
DataOutputStream xdos = new DataOutputStream(xfos);
xdos.writeBytes("ABCDE");	// writes Ascii
xdos.close();

// write ascii data
FileOutputStream afos = new FileOutputStream("test.asc");
byte abytes[] = {65, 66, 67, 68, 69};	// "ABCDE"
afos.write(abytes);			// writes bytes - in this case Ascii
afos.close();

Also, the class StreamTokenizer assumes Ascii input. Thus,

// tokenize an ascii file
FileInputStream fis = new FileInputStream("test.asc");
StreamTokenizer tokenizer = new StreamTokenizer(fis);
int token = tokenizer.nextToken();
System.out.println("token=" + tokenizer.sval);
	// prints "ABCDE"
fis.close();
		
// tokenize an ascii file
// This also works on a DataInputStream
fis = new FileInputStream("test.asc");
DataInputStream dis = new DataInputStream(fis);
tokenizer = new StreamTokenizer(dis);
token = tokenizer.nextToken();
System.out.println("token=" + tokenizer.sval);
	// prints "ABCDE"
dis.close();
		
// attempt to tokenize a Unicode file
fis = new FileInputStream("test.ucd");
tokenizer = new StreamTokenizer(fis);
token = tokenizer.nextToken();
System.out.println("token=" + tokenizer.sval);
	// prints "A" - the tokenizer interprets the high byte of
	// "B" as whitespace
fis.close();
		
// attempt to tokenize a Unicode file by creating a DataInputStream
fis = new FileInputStream("test.ucd");
dis = new DataInputStream(fis);
tokenizer = new StreamTokenizer(dis);
token = tokenizer.nextToken();
System.out.println("token=" + tokenizer.sval);
	// prints "A" - the tokenizer interprets the high byte of
	// "B" as whitespace
dis.close();

You can certainly enter unicode in your Java programme, BUT you have to do it using ASCII characters. The following should work, for example

public class fiddle {
  public static void main(String arg[]) {
    int \u1261 = 1;
    System.out.println("\\"+"u1261 is "+\u1261);
  }
}

(1261 is a Japanese or Chinese character, I think)

How can you read and write binary data?

How can I have my applet display different languages, (e.g. Chinese , Japanese...) using the fonts at the client side?