Use Regular Expressions in JPA CriteriaBuilder

Question

I\'m using the JPA CriteriaBuilder to select entities of type MyEntity from a MySQL db as follows:

String regExp = \"(abc|def)\"
CriteriaBuilder         


        

Answer 1

I came across this recently and used the first post to implement the hibernate mysql function option.

To help save some time for others this is what I did:

set up the function in your custom dialect file in hibernate:

public class MySQLDialect extends Dialect {

   public MySQLDialect() {
      super();
      ...
      registerFunction("regexp", new SQLFunctionTemplate(StandardBasicTypes.INTEGER, "?1 REGEXP ?2"));
      ...
   }
   ...
}

then within the criteria builder section:

CriteriaBuilder builder = ...;    

Pattern regexPattern = Pattern.compile("^[0-9]\\|[0-9]+");

Expression patternExpression = builder.literal(regexPattern.pattern());

Path path = ... ;// regex comparison column

// regexp comes from the name of the regex function 
// defined in the Mysql Dialect file above
Predicate theRegexPredicate = builder.equal(builder.function("regexp", Integer.class, path, patternExpression), 1);

Then use theRegexPredicate to construct the where clause in your CriteriaBuilder query.