A RowMapper for auto-mapping JDBC ResultSet columns to Jackson ObjectNode fields [SPR-9250]

[spring-projects-issues]

Keith Donald opened SPR-9250 and commented

Similar in spirit to the existing BeanPropertyRowMapper, but instead of mapping ResultSet columns to POJOs, we would map directly to Jackson ObjectNode instances.

The main use case is JSON serialization as part of a REST API implementation. In many cases mapping to a JavaBeans model just to write JSON is overkill. It can be a lot simpler to simply convert a JDBC ResultSet to a ObjectNode or List of ObjectNodes. This can be done at present by hand (see (1) below), but this could be automated in many scenarios with a built-in JsonNodeRowMapper implementation that is similar in spirit to BeanPropertyRowMapper.

(1) Manual ResultSet-to-JsonNode mapping example

    @RequestMapping(value="/me/franchises", method=RequestMethod.GET, params="league", produces="application/json")
    public ResponseEntity<? extends Object> qualifyingFranchises(@RequestParam Integer league) {
        if (!SecurityContext.playerSignedIn()) {
            return new ResponseEntity<ErrorBody>(new ErrorBody("not authorized"), HttpStatus.FORBIDDEN);
        }
        List<JsonNode> franchises = jdbcTemplate.query(qualifyingFranchisesSql, new RowMapper<JsonNode>() {
            @Override
            public JsonNode mapRow(ResultSet rs, int rowNum) throws SQLException {
                ObjectNode franchise = mapper.createObjectNode();
                franchise.put("id", rs.getInt("id"));
                franchise.put("name", rs.getString("name"));                
                return franchise;
            }
        }, SecurityContext.getCurrentPlayer().getId(), league);
        return new ResponseEntity<List<JsonNode>>(franchises, HttpStatus.ACCEPTED);
    }

---

Affects: 3.1.1

Reference URL: https://twitter.com/#!/kdonald/status/181918401042726913

1 votes, 2 watchers

[spring-projects-issues]

Chris Beams commented

Hey Keith,

Sounds like a good idea, and would be a perfect chunk of work for a pull request, whether from you or someone else.

[spring-projects-issues]

Keith Donald commented

Basic JsonRowMapper implementation: https://gist.github.com/2137988