private void compileRegex(String regexStr) {
        if (StringUtils.isBlank(regexStr)) {
            throw new IllegalArgumentException("regex must not be empty");
        }
        try {
            this.regex = Pattern.compile(regexStr, Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
            this.regexStr = regexStr;
        } catch (PatternSyntaxException e) {
            throw new IllegalArgumentException("invalid regex "+regexStr, e);
        }
    }
Selector in regex.<br>

@author code4crafter@gmail.com <br>
@since 0.1.0
webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java