Dfyjkt

This is my first time using Spring to add and get data from a database. I have successfully established connection with my database and can add Plants with only id and plantName but now for the part that I do not understand.

How can I create an RowMapper or something else that would work with a loop that would get the Plant and go over all PlantParts to get me the object I need.


I should note that Plant is just an Object I created to ask here to keep it cleaner and easier to answer.

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Plant 
 private Long id;
 private String plantName;
 private List<PlantParts> plantParts;

 public void add(PlantParts plantPartsObj) 
 if (plantParts == null) 
 plantParts = new ArrayList<>();
 

 plantParts.add(plantPartsObj);
 


@Data
@NoArgsConstructor
@AllArgsConstructor
public class PlantParts 
 private String leaves;
 private String pedicle;
 private String petals;

First I create a Plant object with this query:

INSERT INTO PLANTS (id, plantname)
 VALUES (NEXT VALUE FOR sequence, ?);

Then I add multiple PlantParts with this query:

INSERT INTO PLANT_PARTS (id, leaves, pedicle, petals)" +
 " VALUES (?, ?, ?, ?);

And now I am trying to make it all into one Plant object, but I do not get how I can get multiple PlantParts with one RowMapper.

And this would be my code using Spring:

@Repository
public class PlantDao 

 @Autowired
 private JdbcTemplate template;

 @Override
 public Order getPlantById(Long id) 
 String sql = "SELECT plants.id, plants.plantName, plant_parts.id, plant_parts.leaves, plant_parts.pedicle, plant_parts.petals " +
 "FROM plants " +
 "LEFT JOIN plant_parts ON plants.id = plant_parts.id AND plants.id = ?";

 return template.queryForObject(sql, new Object id, getPostRowMapper());

 

 private RowMapper<Plant> getPostRowMapper() 
 return (rs, rowNum) -> new Plant(
 rs.getLong("id"),
 rs.getString("plantname")

 //Check if there are any PlantParts, if yes then go over
 //all of the PlantParts in a loop

 );
 

Now the part that I do not understand is commented out. How can I go over all PlantParts in the RowMapper.

I would like the RowMapper to do something like this after setting id and plantname:

//For the first line
if(rs.getString("leaves") != null)
 plant.add(new PlantRow(rs.getString("leaves"),
 rs.getInt("pedicle"), rs.getInt("petals")));

while (rs.next())
 if(rs.getString("leaves") != null)
 plant.add(new PlantRow(rs.getString("leaves"),
 rs.getInt("pedicle"), rs.getInt("petals")));
 

I do not mind if there is another way to do it, without using RowMapper, I just need something that would make it work.