static public String format(Collection<?> collection, String property){
		return format(collection, property, ",", true);
	}
static public String format ( Collection < ? > collection , String property ) { return format ( collection , property , "," , true ) ; }
Format a collection's elements' properties to ',' separated string, with trimming on the elements' properties<br>
@param collection	The collection that will be formatted
@param property		The property of the collection's element that will be put into the result string.
Please see PropertyUtils.getProperty() of commons-beanutils for detail.
@return	A string containing separated properties of the collection's elements