The URLArgumentLine's PLACEHOLDER_PATTERN doesn't match whitespace after it

[xuanwubing]

usually, we would comment our xxx.yml config's key；
but，if we use placeholder with comment, then the placeholder value must has one whitespace after it at least.

This " private static final Pattern PLACEHOLDER_PATTERN = Pattern.compile("\$\$\{(.+::.*)}$");" regular expression doesn't support any whitespace after placeholder.

[linghengqian]

• I would say this is intentional, I'm a committer to the original SPI implementation, and it was designed to only parse YAML values, not a whole line of YAML.
• I roughly know what implementation you're referring to, and I think you could consider submitting a new SPI implementation for the JDBC Driver. This would completely bypass URLArgumentLine.

[xuanwubing]

I cant agree this is intentional. cause the regular expression[ $${(.+::.*)}$] is not right.
placeholder's regular expression should only match the placeholder itself, no matter what characters before or after it（ps：the regular expression can match placeholder with head characters）.

Anyway, as you said I can implement another for handle this problem！！！Thanks！！！

[linghengqian]

Since I don't see any PR, I'll say I don't know what regular expressions you're referring to should look like.

By the way, there have been changes to the regular expression in this part of the shardingsphere master branch.