我想通过扩展默认值使其在其后设置更多值来制作自己的解串器：
simplified code:
public class Dto {
public String originalJsonString;
}
public MyFooDto extends Dto {
public String myField;
}
@Bean
public ObjectMapper deserializingObjectMapper() {
ObjectMapper objectMapper = new ObjectMapper();
JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addDeserializer(MyFooDto.class, new JsonDtoDeserializer<>());
objectMapper.registerModule(javaTimeModule);
return objectMapper;
}
// or maybe instead of the Beam just @JsonDeserialize(using = JsonDtoDeserializer.class) before MyFooDto?
public class JsonDtoDeserializer<T extends Dto> extends StdDeserializer<T> {
// or maybe extends JsonDeserializer? or UntypedObjectDeserializer? or UntypedObjectDeserializer.Vanilla?
public T deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
// here I would like:
T item = super.deserialize"AsUsual"(p, ctxt);
// the difficulty is to avoid the loop of death, where the deserializer would call itself for the eternity...
// And then set other Dto-fields depending on the original Json input, for example:
item.originalJsonString = p.readValueAsTree().toString();
return item;
}
}
如您所见，我还想将此Dto母类重用于其他DTO。
谢谢社区！
正如沙龙所说（基于我如何从杰克逊的自定义解串器中调用默认解串器）
@Bean
public ObjectMapper serializingObjectMapper() {
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule simpleModule = new SimpleModule();
simpleModule.setDeserializerModifier(new BeanDeserializerModifier() {
@Override
public JsonDeserializer<?> modifyDeserializer(DeserializationConfig config, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
if (Dto.class.isAssignableFrom(beanDesc.getBeanClass())) {
return new JsonDtoDeserializer<>(deserializer, beanDesc.getBeanClass());
}
return deserializer;
}
});
objectMapper.registerModule(simpleModule);
return objectMapper;
}
public class JsonDtoDeserializer<T extends Dto> extends StdDeserializer<T> implements ResolvableDeserializer /*StdDeserializer<Dto<T>>*/ /*UntypedObjectDeserializer.Vanilla*/ /*<T>*/ /*implements ResolvableDeserializer*/ {
private final JsonDeserializer<?> defaultDeserializer;
public JsonDtoDeserializer(JsonDeserializer<?> defaultDeserializer, Class<?> clazz) {
super(clazz);
this.defaultDeserializer = defaultDeserializer;
}
@Override
public T deserialize(JsonParser p, DeserializationContext ctxt)
throws IOException {
@SuppressWarnings("unchecked")
T itemObj = (T) defaultDeserializer.deserialize(p, ctxt);
return itemObj;
}
// for some reason you have to implement ResolvableDeserializer when modifying BeanDeserializer
// otherwise deserializing throws JsonMappingException??
@Override public void resolve(DeserializationContext ctxt) throws JsonMappingException
{
((ResolvableDeserializer) defaultDeserializer).resolve(ctxt);
}
}
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