在维护旧的项目时,由于好久没有使用hibernate,导致很多都比较生疏。自己写sql 查询字段和对象中的属性 需要一一映射。
使用jdbcTemplate.queryForObject()等方法时,有可能报错:Incorrect column count: expected 1, actual 5
1.反例:
StringBuffer sql = new StringBuffer(); sql.append("select pcb.bid, pcb.brand, pcb.brand_code brandCode, pcb.bra_country braCountry, pcb.identifying_photo identifyingPhoto, pcb.bra_letter braLetter, pcb.last_operator_name lastOperatorName,"); sql.append(" pcb.last_operator_id lastOperatorId, pcb.parent_id parentId, pcb.create_time createTime, pcb.update_time updateTime"); sql.append(" from platform_carbrand subpcb inner join platform_carbrand pcb on subpcb.parent_id = pcb.bid"); sql.append(" where subpcb.bid = " + subBrandId);
Carbrand carbrand = jdbcTemplate.queryForObject(sql.toString(), Carbrand.class);
2.解决方式 通过查询多条或一条的正例:
List<Carbrand> carbrandList = jdbcTemplate.query(sql.toString(), new Object[]{}, new BeanPropertyRowMapper<Carbrand>(Carbrand.class)); if (CollectionUtils.isEmpty(carbrandList)) { return null; } return carbrandList.get(0);
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