How to handle jdbc.queryForObject if it doesn't return a row

Question

I would like to know how to properly use jdbc in my case.

The saveLinkHistory column is a bit(1) type in mysql.

public boolean getIsSavedLinkHistory(String name) {
        String sql = "select saveLinkHistory from users where name = ?";
        Boolean isTracked = jdbcTemplateObject.queryForObject(sql, new Object[] { name }, Boolean.class);
        return isTracked;
}

The query worked well until I got an error of Incorrect result size: expected 1, actual 0 because sometimes the name didn't exist, the queryForObject method expects that I ALWAYS get 1 row as a result.

How can I handle this case, just throw an exception that says "name" doesn't exist ? and by the way, is Boolean ok here ? because I didn't see such code before.

Solution 1

Try this:

return DataAccessUtils.singleResult(jdbcTemplate.query(sql, new SingleColumnRowMapper<Boolean>(), param1, param2));

Solution 2

queryForObject method of JdbcTemplate expects that your query should return one row always else it will throw EmptyResultDataAccessException. You can simply use query method with ResultSetExtractor instead of queryForObject. ResultSetExtractor - extractData(ResultSet rs) method would return an arbitrary result object, or null if no data returned. You can throw your relevant exception if it returns null.

 return jdbc.query(sql, new ResultSetExtractor<Boolean>() {
    @Override
    public Boolean extractData(ResultSet rs) throws SQLException,
                                                   DataAccessException {
        return rs.next() ? rs.getBoolean("column_name") : null;
    }
});