1. Find any hexadecimal number in a larger body of text
\b[0-9a-fA-F]+\b
2. Check whether a text string holds just a hexadecimal number
\A[0-9a-fA-F]+\Z
3. Find a hexadecimal number with a 0x prefix
\b0x[0-9a-fA-F]+\b
4. Find a hexadecimal number with an &H prefix
&H[0-9a-fA-F]+\b
5. Find a hexadecimal number with an H suffix
\b[0-9a-fA-F]+H\b
6. Find a hexadecimal byte value or 8-bit number
\b[0-9a-fA-F]{2}\b
7. Find a hexadecimal word value or 16-bit number
\b[0-9a-fA-F]{4}\b
8. Find a hexadecimal double word value or 32-bit number
\b[0-9a-fA-F]{8}\b
9. Find a hexadecimal quad word value or 64-bit number
\b[0-9a-fA-F]{16}\b
10. Find a string of hexadecimal bytes (i.e., an even number of hexadecimal digits)
\b(?:[0-9a-fA-F]{2})+\b
11. Find any hexadecimal number standalone in a larger body of text
(?:^|(?<=\s))[0-9a-fA-F]+(?=$|\s)
[bibliography]
http://blog.csdn.net/guaguastd/article/details/38920565
原文：http://www.cnblogs.com/CarbinHee/p/7712555.html