Java中的字符串到字节

Question

I have a problem in converting String (contains hexadecimal value) to byte . Like below code.

String hexaString = "0xA1";
byte hexaByte = (byte)hexaString;

Not able to convert from String to byte like this code (Getting the Error : Cannot cast from String to byte ).

But i am able to do like this

byte hexaByte = (byte)0xA1; //this is giving output as -95

Anyone please guide me how can i do like the first method(this also output the value -95). Because, the last two digit i will get from db and i need to convert it to hexadecimal(appending 0x). Then i should send to client as a byte value.

Thanks in Advance !

Answer 1

You can do something like:

byte hexaByte = Byte.parseByte("1A", 16);

where 16 is radix (base of system numeration), but if the number is higer than 127 it will cause NumberFormatException.

Answer 2

如果需要使用0x前缀，则(byte) Integer.decode("0xA1")会做正确的事情。