In NamedParameterJdbcTemplate String not mapping properly with BeanPropertyRowMapper

Question

Below is the simple query to get a list of strings.

String sqlQuery = "SELECT TAGS FROM FIN_REQUEST WHERE IS_CORPORATE_CONTENT IS TRUE AND TAGS IS NOT NULL";
List<String> data1 = namedParameterJdbcTemplate.query(sqlQuery, BeanPropertyRowMapper.newInstance(String.class));
List<String> data2 = namedParameterJdbcTemplate.query(sqlQuery, new RowMapper<String>() {
    @Override
    public String mapRow(ResultSet rs, int rowNum) throws SQLException {
        return rs.getString(1);
    }
});

data1 gives an empty list while data2 is giving proper results. I want to avoid RowMapper and use BeanPropertyRowMapper instead.

Answer 1

BeanPropertyRowMapper, as the name implies, is for mapping columns to bean properties. You don't have a wrapper with a field of type String named tags. You are just returning a single String. So you cannot use the BeanPropertyRowMapper.

If you want to use it you need to create a wrapper object, which is probably not what you want. So you need to use the RowMapper. Assuming you are on Java 8 or up you can just use a lambda instead of in anonymous class.

List<String> data2 = namedParameterJdbcTemplate.query(sqlQuery, (rs, row) -> rs.getString(1));

However I see no use for the NamedParameterJdbcTemplate here (there are no named parameters) so you could also use the regular JdbcTemplate instead and use one of its methods.

List<String> data2 = jdbcTemplate.queryForList(sqlQuery, String.class);