还有另一个相当有趣的解决方案,可以在调用默认反序列化器之前修改JSON正文,这可能会很有帮助。假设您需要使用一些附加的bean来完成此操作(使用@Autowire
机制)。
让我们想象一下,您有以下控制器:
@RequestMapping(value = "/order/product", method = POST)
public <T extends OrderProductInterface> RestGenericResponse orderProduct(@RequestBody @Valid T data) {
orderService.orderProduct(data);
return generateResponse();
}
其中OrderProductInterface
是:
@JsonIgnoreProperties(ignoreUnknown = true)
@JsonSerialize(include = NON_EMPTY)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, visible = true, property = "providerType")
@JsonSubTypes({
@JsonSubTypes.Type(value = OrderProductForARequestData.class, name = "A")
})
public interface OrderProductInterface{}
上面的代码将根据字段
providerType
提供动态反序列化并根据具体实现进行验证。为了更好地理解,可以考虑
OrderProductForARequestData
可能是这样的:
public class OrderProductForARequestData implements OrderProductInterface {
@NotBlank(message = "is mandatory field.")
@Getter @Setter
private String providerId;
@NotBlank(message = "is mandatory field.")
@Getter @Setter
private String providerType;
@NotBlank(message = "is mandatory field.")
@Getter @Setter
private String productToOrder;
}
现在,让我们假设我们想要在执行默认反序列化之前以某种方式初始化providerType
(丰富输入),以便对象根据OrderProductInterface
中的规则正确反序列化。为了做到这一点,您只需按以下方式修改@Configuration
类:
@Configuration
public class YourConfiguration{
@Autowired
private ObjectMapper mapper;
@Autowired
private ProviderService providerService;
@Override
public void setup() {
super.setup();
SimpleModule module = new SimpleModule();
module.setDeserializerModifier(new BeanDeserializerModifier() {
@Override
public JsonDeserializer<?> modifyDeserializer(DeserializationConfig config, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
if (beanDesc.getBeanClass() == OrderProductInterface.class) {
return new OrderProductInterfaceDeserializer(providerService, beanDesc);
}
return deserializer;
}
});
mapper.registerModule(module);
}
public static class OrderProductInterfaceDeserializer extends AbstractDeserializer {
private static final long serialVersionUID = 7923585097068641765L;
private final ProviderService providerService;
OrderProductInterfaceDeserializer(roviderService providerService, BeanDescription beanDescription) {
super(beanDescription);
this.providerService = providerService;
}
@Override
public Object deserializeWithType(JsonParser p, DeserializationContext context, TypeDeserializer typeDeserializer) throws IOException {
ObjectCodec oc = p.getCodec();
JsonNode node = oc.readTree(p);
JsonNode tmp = node.get("providerId");
Assert.notNull(tmp, "'providerId' is mandatory field");
String providerId = tmp.textValue();
Assert.hasText(providerId, "'providerId' can't be empty");
((ObjectNode) node).put("providerType",providerService.getProvider(providerId));
JsonFactory jsonFactory = new JsonFactory();
JsonParser newParser = jsonFactory.createParser(node.toString());
newParser.nextToken();
return super.deserializeWithType(newParser, context, typeDeserializer);
}
}
}