I have MySQL column declared as type JSON and I have problems to map it with Jpa/Hibernate. I'm using Spring Boot on back-end.
Here is small part of my code:
@Entity
@Table(name = "some_table_name")
public class MyCustomEntity implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@Column(name = "json_value")
private JSONArray jsonValue;
The program returns me an error and tells me that I can't map the column.
In mysql table the column is defined as:
json_value JSON NOT NULL;
解决方案
I prefer to do this way:
Creating converter (attribute converter) from Map to String and vice versa.
Using Map to map mysql JSON column type in domain (entity) class
The code is bellow.
JsonToMapConverted.java
@Converter
public class JsonToMapConverter
implements AttributeConverter>
{
private static final Logger LOGGER = LoggerFactory.getLogger(JsonToMapConverter.class);
@Override
@SuppressWarnings("unchecked")
public Map convertToDatabaseColumn(String attribute)
{
if (attribute == null) {
return new HashMap<>();
}
try
{
ObjectMapper objectMapper = new ObjectMapper();
return objectMapper.readValue(attribute, HashMap.class);
}
catch (IOException e) {
LOGGER.error("Convert error while trying to convert string(JSON) to map data structure.");
}
return new HashMap<>();
}
@Override
public String convertToEntityAttribute(Map dbData)
{
try
{
ObjectMapper objectMapper = new ObjectMapper();
return objectMapper.writeValueAsString(dbData);
}
catch (JsonProcessingException e)
{
LOGGER.error("Could not convert map to json string.");
return null;
}
}
}
Part of domain (entity-mapping) class
...
@Column(name = "meta_data", columnDefinition = "json")
@Convert(attributeName = "data", converter = JsonToMapConverter.class)
private Map metaData = new HashMap<>();
...
This solution perfectly works for me.