Spring @RestController 自定义 JSON 反序列化器
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【中文标题】Spring @RestController 自定义 JSON 反序列化器【英文标题】:Spring @RestController custom JSON deserializer 【发布时间】:2015-02-17 11:08:45 【问题描述】:我想为某些类(Role 这里)使用自定义 JSON 反序列化器,但我无法让它工作。只是没有调用自定义反序列化程序。
我使用 Spring Boot 1.2。
反序列化器:
public class ModelDeserializer extends JsonDeserializer<Role>
@Override
public Role deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException
return null; // this is what should be called but it isn't
控制器:
@RestController
public class RoleController
@RequestMapping(value = "/role", method = RequestMethod.POST)
public Object createRole(Role role)
// ... this is called
@JsonDeserialize
角色
@JsonDeserialize(using = ModelDeserializer.class)
public class Role extends Model
Jackson2ObjectMapperBuilder
Java 配置中的 bean
@Bean
public Jackson2ObjectMapperBuilder jacksonBuilder()
Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
builder.deserializerByType(Role.class, new ModelDeserializer());
return builder;
我做错了什么?
EDIT这可能是由@RestController
引起的,因为它适用于@Controller
...
【问题讨论】:
【参考方案1】:首先,您无需重写 Jackson2ObjectMapperBuilder
即可添加自定义反序列化程序。当您无法添加@JsonDeserialize
注释时,应使用此方法。您应该使用@JsonDeserialize
或覆盖Jackson2ObjectMapperBuilder
。
缺少的是@RequestBody
注解:
@RestController
public class JacksonCustomDesRestEndpoint
@RequestMapping(value = "/role", method = RequestMethod.POST, consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
@ResponseBody
public Object createRole(@RequestBody Role role)
return role;
@JsonDeserialize(using = RoleDeserializer.class)
public class Role
// ......
public class RoleDeserializer extends JsonDeserializer<Role>
@Override
public Role deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException
// .................
return something;
【讨论】:
我需要做同样的事情,唯一的区别是我有一个 get 方法,在我的 pojo 对象中我使用带有 @JsonDeserialize 的 Date 类型,但是当我运行该方法时,我得到一个 http 400 . (spring 4.1.7 y jackson 2.7.4)【参考方案2】:还有另一个非常有趣的解决方案,如果您想在调用默认反序列化器之前修改 JSON 主体,它会很有帮助。让我们假设您需要为此使用一些额外的 bean(使用 @Autowire
机制)
让我们想象一下你有以下控制器的情况:
@RequestMapping(value = "/order/product", method = POST)
public <T extends OrderProductInterface> RestGenericResponse orderProduct(@RequestBody @Valid T data)
orderService.orderProduct(data);
return generateResponse();
OrderProductInterface
在哪里:
@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
上面的代码将提供基于providerType
的动态反序列化,并根据具体实现进行验证。为了更好地掌握,请考虑OrderProductForARequestData
可以是这样的:
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;
现在让我们想象一下,我们想要以某种方式初始化providerType
(丰富输入)在执行默认反序列化之前。因此对象将根据OrderProductInterface
中的规则正确反序列化。
为此,您可以通过以下方式修改您的 @Configuration
类:
//here can be any annotation which will enable MVC/Boot
@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);
//Let's image that we have some identifier for provider type and we want to detect it
JsonNode tmp = node.get("providerId");
Assert.notNull(tmp, "'providerId' is mandatory field");
String providerId = tmp.textValue();
Assert.hasText(providerId, "'providerId' can't be empty");
// Modify node
((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);
【讨论】:
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