我在应用程序MySQL 5.7中使用,并且具有JSON列。当我尝试运行集成测试时,由于H2数据库无法创建表,因此无法进行测试。这是错误:
2016-09-21 16:35:29.729 ERROR 10981 --- [ main] org.hibernate.tool.hbm2ddl.SchemaExport : HHH000389: Unsuccessful: create table payment_transaction (id bigint generated by default as identity, creation_date timestamp not null, payload json, period integer, public_id varchar(255) not null, state varchar(255) not null, subscription_id_zuora varchar(255), type varchar(255) not null, user_id bigint not null, primary key (id)) 2016-09-21 16:35:29.730 ERROR 10981 --- [ main] org.hibernate.tool.hbm2ddl.SchemaExport : Unknown data type: "JSON"; SQL statement:
这是实体类。
@Table(name = "payment_transaction") public class PaymentTransaction extends DomainObject implements Serializable { @Convert(converter = JpaPayloadConverter.class) @Column(name = "payload", insertable = true, updatable = true, nullable = true, columnDefinition = "json") private Payload payload; public Payload getPayload() { return payload; } public void setPayload(Payload payload) { this.payload = payload; } }
和子类:
public class Payload implements Serializable { private Long userId; private SubscriptionType type; private String paymentId; private List<String> ratePlanId; private Integer period; public Long getUserId() { return userId; } public void setUserId(Long userId) { this.userId = userId; } public SubscriptionType getType() { return type; } public void setType(SubscriptionType type) { this.type = type; } public String getPaymentId() { return paymentId; } public void setPaymentId(String paymentId) { this.paymentId = paymentId; } public List<String> getRatePlanId() { return ratePlanId; } public void setRatePlanId(List<String> ratePlanId) { this.ratePlanId = ratePlanId; } public Integer getPeriod() { return period; } public void setPeriod(Integer period) { this.period = period; } }
并将此转换器插入数据库:
public class JpaPayloadConverter implements AttributeConverter<Payload, String> { // ObjectMapper is thread safe private final static ObjectMapper objectMapper = new ObjectMapper(); private Logger log = LoggerFactory.getLogger(getClass()); @Override public String convertToDatabaseColumn(Payload attribute) { String jsonString = ""; try { log.debug("Start convertToDatabaseColumn"); // convert list of POJO to json jsonString = objectMapper.writeValueAsString(attribute); log.debug("convertToDatabaseColumn" + jsonString); } catch (JsonProcessingException ex) { log.error(ex.getMessage()); } return jsonString; } @Override public Payload convertToEntityAttribute(String dbData) { Payload payload = new Payload(); try { log.debug("Start convertToEntityAttribute"); // convert json to list of POJO payload = objectMapper.readValue(dbData, Payload.class); log.debug("JsonDocumentsConverter.convertToDatabaseColumn" + payload); } catch (IOException ex) { log.error(ex.getMessage()); } return payload; } }
提出问题后,H2添加了JSON支持,版本为1.4.200(2019-10-14)。
但是,您很少需要在数据库中使用JSON数据类型。JSON本质上只是一个可能很长的字符串,因此您可以使用大多数数据库都可用的CLOB。
如果需要对它们进行操作的SQL函数,并且仅在数据库坚持认为其JSON函数对JSON类型而不是对CLOB进行操作时,才需要JSON数据类型。但是,此类功能往往依赖于数据库。