Possibly lossy conversion from int to byte
I am trying to write hex data to my serial port using java, but now I cannot convert the hex data to a byte array.
Here is the code that shows the error message:
static byte[] bytearray = {0x02, 0x08, 0x16, 0x0, 0x00, 0x33, 0xC6, 0x1B};
This is the code writing to the serial port:
try {
outputStream = serialPort.getOutputStream();
// Write the stream of data conforming to PC to reader protocol
outputStream.write(bytearray);
outputStream.flush();
System.out.println("The following bytes are being written");
for(int i=0; i<bytearray.length; i++){
System.out.println(bytearray[i]);
System.out.println("Tag will be read when its in the field of the reader");
}
} catch (IOException e) {}
May I know how to solve this problem. I am currently using the javax.comm plugin. Thank.
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2 answers
If you look at the error message:
Main.java:10: error: incompatible types: possible lossy conversion from int to byte
static byte[] bytearray = {0x02, 0x08, 0x16, 0x0, 0x00, 0x33, 0xC6, 0x1B};
^
There is a small caret to indicate the value 0xC6
. The reason for this question is that java is byte
signed, which means its range is -0x80 to 0x7F. You can fix this by saying:
static byte[] bytearray = {0x02, 0x08, 0x16, 0x0, 0x00, 0x33, (byte) 0xC6, 0x1B};
Or, you can use a negative value within the -0x3A range (which is equivalent to 0x36 in two-digit notation).
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