keyHolder.getKey () renvoie null

Question

Pourquoi le code de "Spring in action 5" ne fonctionne pas (keyHolder.getKey () renvoie null, mais l'entité est enregistrée dans la base de données)?

private long savePizzaInfo(Pizza pizza) {
    pizza.setCreatedAt(new Date());
    PreparedStatementCreator psc =
            new PreparedStatementCreatorFactory(
                    "insert into PIZZA (name, createdAt) values (?, ?)",
                    Types.VARCHAR, Types.TIMESTAMP
            ).newPreparedStatementCreator(
                    Arrays.asList(
                            pizza.getName(),
                            new Timestamp(pizza.getCreatedAt().getTime())));
    KeyHolder keyHolder = new GeneratedKeyHolder();
    template.update(psc, keyHolder);
    return keyHolder.getKey().longValue();
}

Ma table DB:

CREATE TABLE PIZZA
(
ID bigint DEFAULT (NEXT VALUE FOR 
PUBLIC.SYSTEM_SEQUENCE_12CA966F_4FFD_469C_BA69_80BB93916EF3) AUTO_INCREMENT 
PRIMARY KEY NOT NULL,
NAME varchar(50) NOT NULL,
CREATEDAT timestamp NOT NULL
);
CREATE UNIQUE INDEX PRIMARY_KEY_4 ON PIZZA (ID);

Answer 1

Vous devez demander à l'instance PreparedStatementCreatorFactory de renvoyer les clés générées:

PreparedStatementCreatorFactory preparedStatementCreatorFactory = new PreparedStatementCreatorFactory(
         "insert into PIZZA (name, createdAt) values (?, ?)",
         Types.VARCHAR, Types.TIMESTAMP
 );

// By default, returnGeneratedKeys = false so change it to true
preparedStatementCreatorFactory.setReturnGeneratedKeys(true);

 PreparedStatementCreator psc =
         preparedStatementCreatorFactory.newPreparedStatementCreator(
                    Arrays.asList(
                            pizza.getName(),
                            new Timestamp(pizza.getCreatedAt().getTime())));

Answer 2

Vous devez spécifier votre déclaration préparée, notez la déclaration.RETURN_GENERATED_KEYS dans le code ci-dessous, vous avez besoin de quelque chose comme ça

final PreparedStatementCreator psc = new PreparedStatementCreator() {
      @Override
      public PreparedStatement createPreparedStatement(final Connection connection) throws SQLException {
        final PreparedStatement ps = connection.prepareStatement("INSERT INTO `names` (`name`) VALUES (?)",
            Statement.RETURN_GENERATED_KEYS);
        ps.setString(1, name);
        return ps;
      }
    };

Answer 3

Pourquoi ne pas utiliser SimpleJdbcInsert à la place?

dbcInsert = new SimpleJdbcInsert(jdbcTemplate);
        jdbcInsert.withTableName("TABLE_NAME").usingGeneratedKeyColumns(
                "Primary_key");
        Map<String, Object> parameters = new HashMap<>();
        parameters.put("Column_NAME1", bean.getval1());
        parameters.put("Column_NAME2", bean.getval2());
        // execute insert
        Number key = jdbcInsert.executeAndReturnKey(new MapSqlParameterSource(
                parameters));
           // convert Number to Int using ((Number) key).intValue()
            return ((Number) key).intValue();