what does double star regex means in spring security url

Question

i recently came across a spring project where i saw a security configuration like following

<intercept-url pattern="/register/**" access="permitAll()" />

After google and digging more i was not able to find out what the double star means /register/** It would be great if anybody could explain me. What is the significance of stars in urls spring security.

Answer 1

These patters are Ant-style path patterns (https://ant.apache.org/manual/dirtasks.html#patterns). The ** matches zero or more 'directories' in a path, take a look at AntPathMatcher