Re: how to get the folder or file modified date as timestamp from a site?
By default values are stored as timestamp in the DB. You need to extract the values and convert to any format you want.
Use Java backed APIs to get the cm:modified property using the nodeRefs of a folder/file. The value is of type Serializable and when you cast it to java.util.Date, you would get the timestamp automatically.
Date modifiedDate = (Date) properties.get(ContentModel.PROP_MODIFIED);
You can parse and convert the above date to any format you want as per your requirement.