[JAVA] Create your own encode for String.getBytes ()

Create your own encode for String.getBytes ()

--The character code of the opponent system is SJIS, and it was necessary to send the characters that are garbled at the Unicode code point. --It is judged that it is faster to replace at the time of encoding than to replace twice.

private static final Map<Character, byte[]>  conversionCharsetMap = new LinkedHashMap<Character, byte[]>(){
	{
		put('～', new byte[]{(byte) 0x81, (byte) 0x60});
		put('－', new byte[]{(byte) 0x81, (byte) 0x7C});
		put('￠', new byte[]{(byte) 0x81, (byte) 0x91});
		put('￡', new byte[]{(byte) 0x81, (byte) 0x92});
		put('￢', new byte[]{(byte) 0x81, (byte) 0xCA});
		put('―', new byte[]{(byte) 0x81, (byte) 0x5C});
		put('∥', new byte[]{(byte) 0x81, (byte) 0x61});
	}
 };

public byte[] encode(String str, String charsetName){

	Charset charset = Charset.forName(charsetName);

	CharsetEncoder encoder = charset.newEncoder();

	CharBuffer inBuf = CharBuffer.wrap(str);

	ByteBuffer outBuf = ByteBuffer.allocate(inBuf.length() * (int)encoder.maxBytesPerChar());

	CoderResult result;

	//Loop while CoderResult returns an error
	while((result = encoder.encode(inBuf, outBuf, true)).isError()) {

		//reset
		encoder.reset();

		//If mapping is not possible
		//For example, TF-8⇒SJIS(Not MS932)Characters that fail in ~ ∥－￠￡￢― etc. Enter here
		if(result.isUnmappable()) {

			//Get 1 character (character that failed to map)
			char ch = inBuf.get();
			byte[] val = null;

			//Put the processing of what to do if mapping fails in this area
			//Here, the bytecode for SJIS of the character that failed to be mapped is obtained from the map.
			val = conversionCharsetMap.get(ch);


			//Put to byte buffer for encoding result
			outBuf.put(val);
		}
		//Illegal input
		if(result.isMalformed()) {
			//This is basically rare.
		}
	}

	//Flash to encoding result buffer
	encoder.flush(outBuf);

	//Flip the buffer(Invert)Return to start position
	outBuf.flip();

	return Arrays.copyOf(outBuf.array(), outBuf.limit());
}