Adding non printable chars to a string in Java?

Question

I need to add some non printable chars to a string in java so it can be sent down a tcp pipe. the chars mean something to the protocol I am using (record separator and end of message respectively)

what is the best way to go about doing this?

Ideally I'l like to refer to them as constants so that I can use string concatonation/stringbuilder/string.format to add them where required, without having to type them out.

For the curious the chars I need are ASCIIx1E (Record separator) and ACSIIx03 (End of Text).

Solution 1

public final class ProtocolConstants {
    public final char RECORD_SEPARATOR = 0x1e;
    public final char END_OF_TEXT = 0x03;

    private ProtocolConstants() {}
}

something like that?

Solution 2

If you wish, you can write these as Unicode literals (in chars or Strings):

final String endOfText = "\u0003";

• Unicode charts
• Java Language Specification Lexical Structure chapter

I am assuming that you don't literally want ASCII for a byte-based protocol (the chars are still 16 bits).

Solution 3

You can add any chars to a Java String. But a String is probably not what you want if you just want to transmit binary data. Consider using a byte[] or some other byte-oriented interface.