单体映射为Map，数组映射为List

1.Map的映射

1.使用Map数据类型

private Map<String, Object> specs;

2.编写一个MapAndJson类进行转换

该类实现了AttributeConverter<>接口

public class MapAndJson implements AttributeConverter<Map<String,Object>,String> {
}

3.在类中调用ObjectMapper的方法完成格式之间的相互转换

public class MapAndJson implements AttributeConverter<Map<String,Object>,String> {
    @Autowired
    private ObjectMapper mapper;
    @Override
    public String convertToDatabaseColumn(Map<String, Object> stringObjectMap) {
        try {
            return mapper.writeValueAsString(stringObjectMap);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            throw new ServerErrorException(9999);
        }
    }
    @Override
    public Map<String, Object> convertToEntityAttribute(String s) {
        try {
            return mapper.readValue(s, HashMap.class);
        } catch (JsonProcessingException e) {
            throw new ServerErrorException(9999);
        }
    }
}

4.使用@Convert注解注入

 @Convert(converter = MapAndJson.class)
    private Map<String, Object> specs;

2.List的映射：

大体与Map相同，但在映射类中代码需要更改

@Converter
public class ListAndJson implements AttributeConverter<List<Object>,String> {
    @Autowired
    private ObjectMapper mapper;
    @Override
    public String convertToDatabaseColumn(List<Object> objects) {
        try {
            return mapper.writeValueAsString(objects);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            throw new ServerErrorException(9999);
        }
    }
    @Override
    public List<Object> convertToEntityAttribute(String s) {
        try {
            if (s == null){
                return null;
            }
            List<Object> t =  mapper.readValue(s,List.class);
            return t;
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            throw new ServerErrorException(9999);
        }
    }
}