Java：验证某个字符串模式

Question

I am trying to validate a string in a 'iterative way' and all my tryouts just fail! I find it a bit complicated and i'm guessing maybe you could teach me how to do it right. I assume that most of you will suggest me to use regex patterns but i dont really know how, and in general, how can a regex be defined for infinite "sets"?

The string i want to validate is "ANYTHING|NUMBER_ONLY,ANYTHING|NUMBER_ONLY..."

for example: "hello|5,word|10" and "hello|5,word|10," are both valid.

note: I dont mind if the string ends with or without a comma ','.

Answer 1

I'd suggest splitting your string to array by | delimiter. And validate each part separately. Each part (except first one) should match following pattern \\d+(,.*)?

UPDATED

Split by , and validate each part with .*|\\d+

Answer 2

Kleene star ( * ) lets you define "infinite sets" in regular expressions. Following pattern should do the trick:

[^,|]+\|\d+(,[^,|]+\|\d+)*,?
A----------B--------------C-

Part A matches the first element. Part B matches any following elements (notice the star). Part C is the optional comma at the end.

WARNING: Remember to escape backslashes in Java string.