不要用陌生人的目光来看你所爱的人，也不要认为自己做出了牺牲——贝·列昂尼多娃
例如这里使用hutool的EnumUtil.getEnumAt传入枚举的ordinal，以及枚举类型，获取到具体的枚举常量值
import cn.hutool.core.util.EnumUtil;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.deser.ContextualDeserializer;
import java.io.IOException;
/**
* @author VampireAchao
* @since 2023/1/12 15:46
*/
public class EnumOrdinalDeSerializer<E extends Enum<E>> extends JsonDeserializer<E> implements ContextualDeserializer {
private JavaType type;
public EnumOrdinalDeSerializer() {
}
public EnumOrdinalDeSerializer(JavaType type) {
this.type = type;
}
/**
* Method that can be called to ask implementation to deserialize
* JSON content into the value type this serializer handles.
* Returned instance is to be constructed by method itself.
* <p>
* Pre-condition for this method is that the parser points to the
* first event that is part of value to deserializer (and which
* is never JSON 'null' literal, more on this below): for simple
* types it may be the only value; and for structured types the
* Object start marker or a FIELD_NAME.
* </p>
* <p>
* The two possible input conditions for structured types result
* from polymorphism via fields. In the ordinary case, Jackson
* calls this method when it has encountered an OBJECT_START,
* and the method implementation must advance to the next token to
* see the first field name. If the application configures
* polymorphism via a field, then the object looks like the following.
* <pre>
* {
* "@class": "class name",
* ...
* }
* </pre>
* Jackson consumes the two tokens (the <tt>@class</tt> field name
* and its value) in order to learn the class and select the deserializer.
* Thus, the stream is pointing to the FIELD_NAME for the first field
* after the @class. Thus, if you want your method to work correctly
* both with and without polymorphism, you must begin your method with:
* <pre>
* if (p.currentToken() == JsonToken.START_OBJECT) {
* p.nextToken();
* }
* </pre>
* This results in the stream pointing to the field name, so that
* the two conditions align.
* <p>
* Post-condition is that the parser will point to the last
* event that is part of deserialized value (or in case deserialization
* fails, event that was not recognized or usable, which may be
* the same event as the one it pointed to upon call).
* <p>
* Note that this method is never called for JSON null literal,
* and thus deserializers need (and should) not check for it.
*
* @param p Parsed used for reading JSON content
* @param ctxt Context that can be used to access information about
* this deserialization activity.
* @return Deserialized value
*/
@Override
public E deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
return EnumUtil.getEnumAt((Class<E>) type.getRawClass(), p.getValueAsInt());
}
/**
* Method called to see if a different (or differently configured) deserializer
* is needed to deserialize values of specified property.
* Note that instance that this method is called on is typically shared one and
* as a result method should <b>NOT</b> modify this instance but rather construct
* and return a new instance. This instance should only be returned as-is, in case
* it is already suitable for use.
*
* @param ctxt Deserialization context to access configuration, additional
* deserializers that may be needed by this deserializer
* @param property Method, field or constructor parameter that represents the property
* (and is used to assign deserialized value).
* Should be available; but there may be cases where caller cannot provide it and
* null is passed instead (in which case impls usually pass 'this' deserializer as is)
* @return Deserializer to use for deserializing values of specified property;
* may be this instance or a new instance.
* @throws JsonMappingException
*/
@Override
public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property) throws JsonMappingException {
//beanProperty is null when the type to deserialize is the top-level type or a generic type, not a type of a bean property
JavaType type = ctxt.getContextualType() != null
? ctxt.getContextualType()
: property.getMember().getType();
return new EnumOrdinalDeSerializer<>(type);
}
}
使用：
代码语言：javascript复制class Entity{
@JsonDeserialize(using = EnumOrdinalDeSerializer.class)
private MyEnum myEnum;
}
