I have some regex that I need to convert from mysql to java, but they don't work when passed to String.matches().
How do I convert a mysql regex to a java regex?
Is there any APIs (built-in or third-party) to do this?
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Man ! It would be mandatory for you to post your attempts (precisely concise code snippets).Lion– Lion2012-01-06 04:40:25 +00:00Commented Jan 6, 2012 at 4:40
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1 Answer
It's really simple. Here's the difference:
- Java's
String.matches()needs to match the whole String - mysql's
regexponly needs to match part of the string
To convert a mysql regex into a java one, basically add ".*" to each end of the regex, or otherwise convert it from a "partial" match to a full match.
Here's some examples to demonstrate:
Java
"xyz".matches("y"); // false - only matches part of the input
"xyz".matches(".*y.*"); // true
"xyz".matches("[xyz]"); // false - only matches one char, but String is 3 chars
"xyz".matches("[xyz]+"); // true
mysql
select 'xyz' regexp 'y'; -- 1 (ie true)
select 'xyz' regexp '.*y.*'; -- 1 (ie true)
select 'xyz' regexp '[xyz]'; -- 1 (ie true)
select 'xyz' regexp '[xyz]+'; -- 1 (ie true)