How to create a generic date formatter in java for Solr?
date, date-format, java, solr
Solution
I just try the various formats until I get a hit:
public static String toUtcDate(String dateStr) {
SimpleDateFormat out = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
// Add other parsing formats to try as you like:
String[] dateFormats = {"yyyy-MM-dd", "MMM dd, yyyy hh:mm:ss Z"};
for (String dateFormat : dateFormats) {
try {
return out.format(new SimpleDateFormat(dateFormat).parse(dateStr));
} catch (ParseException ignore) { }
}
throw new IllegalArgumentException("Invalid date: " + dateStr);
}
I'm not aware of a library that does this.
Problem
I've a requirement where date can be passed in the following formats before indexing them to Solr. Here are the examples of dates being passed ``` String dateStr = "2012-05-23T00:00:00-0400"; String dateStr1 = "May 24, 2012 04:57:40 GMT"; String dateStr2 = "2011-06-21"; ``` The standard Solr format is "yyyy-MM-dd'T'HH:mm:ss'Z'". I've tried SimpleDateFormat but is not able to write a generic program to support various formats. It ends up throwing parse exceptions. I also tried joda time, but not been succeful so far in UTC conversion. ``` public static String toUtcDate(final String iso8601) { DateTime dt = ISO_PARSE_FORMAT.parseDateTime(iso8601); DateTime utcDt = dt.withZone(ZONE_UTC); return utcDt.toString(ISO_PRINT_FORMAT); } ``` Is there a standard library to achieve this ? Any pointers will be appreciated. Thanks