https://download.csdn.net/download/chongchi_wxcc/86618299
YModem下载，可直接使用android studio 导入为module，使用时可直接调用YModem.java中的
send（File file）方法
在开发中，遇到需要在APP中用YModem协议进行固件升级的需求，记录一下
1、首先看一下YModem协议的传输过程
上图就是YModem协议的正常传输文件的过程
2、传输过程中的数据包格式
（1） 文件信息数据包格式
（2）文件流数据包格式
发送文件流数据包，序号从01开始，依次叠加1， 直到文件去读取发送结束
（3）全0数据包
注：
NAK（0x15）若在数据传输过程中收到NAK，需要再次将数据包发送个下位机
CAN（0x18） 若在数据传输过程中收到CAN，可直接中断传输了
3、代码
public boolean send(File file) {
try {
CRC crc = new CRC16();
//发送文件信息数据包
String fileNameString = file.getName() + (char)0 + file.length();
byte[] fileNameBytes = Arrays.copyOf(fileNameString.getBytes(), 128);
modem.sendFileInfo(0, Arrays.copyOf(fileNameBytes, 128), 128, crc);
Thread.sleep(20);
//发送文件流数据包
byte[] block = new byte[1024];
DataInputStream dataStream = new DataInputStream(new FileInputStream(file));
modem.sendDataBlocks(dataStream, 1, crc, block);
Thread.sleep(20);
//发送EOT
modem.sendEOT();
Thread.sleep(20);
//发送全0数据包
modem.sendFileZero();
return true;
}catch (Exception e) {
e.printStackTrace();
}
return false;
}
public class CRC16 implements CRC {
private static int[] table = {
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0,
};
@Override
public int getCRCLength() {
return 2;
}
@Override
public long calcCRC(byte[] block) {
int crc = 0x0000;
for (byte b : block) {
crc = ((crc << 8) ^ table[((crc >> 8) ^ (0xff & b))]) & 0xFFFF;
}
return crc;
}
}
class Modem {
/* Protocol characters used */
protected static final byte SOH = 0x01; /* Start Of Header */
protected static final byte STX = 0x02; /* Start Of Text (used like SOH but means 1024 block size) */
protected static final byte EOT = 0x04; /* End Of Transmission */
protected static final byte ACK = 0x06; /* ACKnowlege */
protected static final byte NAK = 0x15; /* Negative AcKnowlege */
protected static final byte CAN = 0x18; /* CANcel character */
protected static final byte CPMEOF = 0x1A;
protected static final byte ST_C = 'C';
protected static final int MAXERRORS = 10;
private InputStream inputStream;
private OutputStream outputStream;
private boolean isReading = true;
/**
* Constructor
*
* @param inputStream stream for reading received data from other side
* @param outputStream stream for writing data to other side
*/
protected Modem(InputStream inputStream, OutputStream outputStream) {
this.inputStream = inputStream;
this.outputStream = outputStream;
isReading = true;
}
protected void sendDataBlocks(DataInputStream dataStream, int blockNumber, CRC crc, byte[] block) throws IOException {
int dataLength;
while ((dataLength = dataStream.read(block)) != -1) {
sendBlock(blockNumber++, block, dataLength, crc);
}
}
public void sendFileZero() throws IOException {
int errorCount = 0;
int character;
while (errorCount < 6) {
byte seq = 0x00;
byte[] data = YModemUtils.getDataPackage(new byte[128], 128, seq, new CRC16());
outputStream.write(data);
outputStream.flush();
try {
character = readByte();
if (character == ACK) {
break;
} else if (character == CAN) {
throw new IOException("Transmission terminated");
}
} catch (Exception ignored) {
}
errorCount++;
}
}
protected void sendEOT() throws IOException {
int errorCount = 0;
int character;
while (errorCount < 10) {
sendByte(EOT);
try {
character = readByte();
if (character == ACK) {
return;
} else if (character == CAN) {
throw new IOException("Transmission terminated");
}
} catch (Exception ignored) {
}
errorCount++;
}
}
protected void sendFileInfo(int blockNumber, byte[] block, int dataLength, CRC crc) throws IOException {
int errorCount;
byte character;
if (dataLength < block.length) {
block[dataLength] = CPMEOF;
}
errorCount = 0;
while (errorCount < MAXERRORS)
{
byte head;
if (block.length == 1024) {
head = STX;
} else { //128
head = SOH;
}
byte[] headByte = YModemUtils.getDataHeader(ChatUtils.intToBytes(blockNumber)[0], head);
byte[] crcbyte = writeCRC(block, crc);
byte[] fileData = YModemUtils.concat(headByte, block, crcbyte);
outputStream.write(fileData);
outputStream.flush();
boolean receiveACK = false;
while (true) {
try {
character = readByte();
if (character == ACK) {
receiveACK = true;
} else if (character == NAK) {
errorCount++;
shortSleepTime(10);
break;
} else if (character == ST_C) {
if(receiveACK) {
shortSleepTime(10);
return;
} else {
errorCount++;
shortSleepTime(10);
break;
}
} else if (character == CAN) {
throw new IOException("Transmission terminated");
}else {
throw new IOException("Transmission terminated");
}
} catch (Exception e) {
errorCount++;
break;
}
}
}
throw new IOException("Too many errors caught, abandoning transfer");
}
protected void sendBlock(int blockNumber, byte[] block, int dataLength, CRC crc) throws IOException {
int errorCount;
byte character;
if (dataLength < block.length) {
block[dataLength] = CPMEOF;
}
errorCount = 0;
while (errorCount < MAXERRORS)
{
byte head;
if (block.length == 1024) {
head = STX;
} else { //128
head = SOH;
}
byte[] headByte = YModemUtils.getDataHeader(ChatUtils.intToBytes(blockNumber)[0], head);
byte[] crcbyte = writeCRC(block, crc);
byte[] fileData = YModemUtils.concat(headByte, block, crcbyte);
outputStream.write(fileData);
outputStream.flush();
while (true) {
try {
character = readByte();
if (character == ACK) {
shortSleepTime(10);
return;
} else if (character == NAK) {
errorCount++;
shortSleepTime(10);
break;
} else if (character == ST_C) {
errorCount++;
shortSleepTime(10);
break;
} else if (character == CAN) {
throw new IOException("Transmission terminated");
}else {
throw new IOException("Transmission terminated");
}
} catch (Exception e) {
errorCount++;
break;
}
}
}
throw new IOException("Too many errors caught, abandoning transfer");
}
protected void sendByte(byte b) throws IOException {
outputStream.write(b);
outputStream.flush();
}
private void shortSleep() {
try {
Thread.sleep(2);
} catch (InterruptedException e) {
try {
interruptTransmission();
} catch (IOException ignore) {
}
throw new RuntimeException("Transmission was interrupted", e);
}
}
private byte readByte() throws IOException {
while (isReading) {
if (inputStream != null && inputStream.available() > 0) {
int b = inputStream.read();
return (byte) b;
}
shortSleep();
}
throw new IOException("read end");
}
}