您作为资深java专家，请使用java的 <groupId>net.digger</groupId> <artifactId>utils</artifactId> 包，编写ymodem文件传输工具类，方便调用

好的，下面是一个简单的ymodem文件传输工具类的实现，使用了net.digger.utils包中的一些工具类： ```java package com.example.ymodem; import net.digger.util.Hex; import net.digger.util.HexFormatException; import java.io.*; import java.nio.charset.StandardCharsets; import java.util.Arrays; public class YModemTransfer { private static final int PACKET_SIZE = 1024; private static final int PACKET_OVERHEAD = 3; private static final int PACKET_DATA_SIZE = PACKET_SIZE - PACKET_OVERHEAD; private static final byte SOH = 0x01; private static final byte STX = 0x02; private static final byte EOT = 0x04; private static final byte ACK = 0x06; private static final byte NAK = 0x15; private static final byte CAN = 0x18; private static final byte CRC = 0x43; private static final byte ABORT = 0x41; private final InputStream in; private final OutputStream out; public YModemTransfer(InputStream in, OutputStream out) { this.in = in; this.out = out; } public void sendFile(File file) throws IOException, InterruptedException { FileInputStream fis = new FileInputStream(file); BufferedInputStream bis = new BufferedInputStream(fis); sendHeader(file.getName(), file.length()); byte[] buffer = new byte[PACKET_DATA_SIZE]; int bytesRead; int packetNumber = 0; while ((bytesRead = bis.read(buffer)) != -1) { byte[] packet = createPacket(packetNumber, buffer, bytesRead); int attempts = 0; boolean success = false; while (!success && attempts < 10) { out.write(packet); int response = in.read(); if (response == ACK) { success = true; } else if (response == NAK) { attempts++; } else { throw new IOException("Unexpected response: " + response); } } if (!success) { throw new IOException("Failed to send packet"); } packetNumber++; } sendEOT(); bis.close(); fis.close(); } private void sendHeader(String fileName, long fileSize) throws IOException, InterruptedException { byte[] header = createHeader(fileName, fileSize); int attempts = 0; boolean success = false; while (!success && attempts < 10) { out.write(header); int response = in.read(); if (response == ACK) { success = true; } else if (response == NAK) { attempts++; } else { throw new IOException("Unexpected response: " + response); } } if (!success) { throw new IOException("Failed to send header"); } } private void sendEOT() throws IOException, InterruptedException { int attempts = 0; boolean success = false; while (!success && attempts < 10) { out.write(EOT); int response = in.read(); if (response == ACK) { success = true; } else if (response == NAK) { attempts++; } else { throw new IOException("Unexpected response: " + response); } } if (!success) { throw new IOException("Failed to send EOT"); } } private static byte[] createPacket(int packetNumber, byte[] data, int dataSize) throws IOException { if (dataSize > PACKET_DATA_SIZE) { throw new IllegalArgumentException("Data too large for packet"); } ByteArrayOutputStream baos = new ByteArrayOutputStream(); baos.write(dataSize == PACKET_DATA_SIZE ? STX : SOH); baos.write(packetNumber & 0xff); baos.write((~packetNumber) & 0xff); baos.write(data, 0, dataSize); byte[] crc = calculateCrc(data, dataSize); baos.write(crc[0]); baos.write(crc[1]); return baos.toByteArray(); } private static byte[] createHeader(String fileName, long fileSize) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); baos.write(SOH); baos.write(0); baos.write(~0); byte[] fileNameBytes = fileName.getBytes(StandardCharsets.US_ASCII); if (fileNameBytes.length > 128) { throw new IllegalArgumentException("File name too long"); } baos.write(fileNameBytes); for (int i = 0; i < 128 - fileNameBytes.length; i++) { baos.write(0); } byte[] fileSizeBytes = Long.toString(fileSize).getBytes(StandardCharsets.US_ASCII); if (fileSizeBytes.length > 10) { throw new IllegalArgumentException("File size too large"); } for (int i = 0; i < 10 - fileSizeBytes.length; i++) { baos.write(0); } baos.write(fileSizeBytes); for (int i = 0; i < 128 - fileSizeBytes.length; i++) { baos.write(0); } byte[] crc = calculateCrc(Arrays.copyOfRange(baos.toByteArray(), 3, 131), 128); baos.write(crc[0]); baos.write(crc[1]); return baos.toByteArray(); } private static byte[] calculateCrc(byte[] data, int dataSize) throws IOException { try { int crc = 0; for (int i = 0; i < dataSize; i++) { crc = updateCrc(crc, data[i]); } return Hex.toByteArray(Integer.toHexString(crc & 0xffff).toUpperCase()); } catch (HexFormatException e) { throw new IOException("Failed to calculate CRC", e); } } private static int updateCrc(int crc, byte data) { crc = crc ^ ((int) data << 8); for (int i = 0; i < 8; i++) { if ((crc & 0x8000) != 0) { crc = (crc << 1) ^ 0x1021; } else { crc = crc << 1; } } return crc & 0xffff; } } ``` 这个类包含了一个sendFile方法，它将给定的文件通过YModem协议传输到输出流中。要使用该方法，只需将输入流和输出流传递给YModemTransfer的构造函数，然后调用sendFile方法即可。 例如，以下代码将文件"example.bin"通过YModem协议传输到串口： ```java SerialPort port = ...; // 获取串口对象 YModemTransfer transfer = new YModemTransfer(port.getInputStream(), port.getOutputStream()); transfer.sendFile(new File("example.bin")); ```