Performs a search, with the requirement that the search shall return a single directory entry, and uses the supplied mapper to create the object from that entry.
Ignores PartialResultException if thrown, for compatibility with Active Directory (see {@link LdapTemplate#setIgnorePartialResultException(boolean)}).
@param base the search base, relative to the base context supplied by the context source.
@param filter the LDAP search filter
@param params parameters to be substituted in the search.
@return a DirContextOperations instance created from the matching entry.
@throws IncorrectResultSizeDataAccessException if no results are found or the search returns more than oneresult.