我目前正在嘗試使用能夠處理多態(tài)性的杰克遜（Jackson）實(shí)現(xiàn)反序列化器，也就是說，給定這兩個(gè)類：public abstract class Animal {  private String name;  private float weight;  @JsonCreator  protected Animal(@JsonProperty(value="name") String name, @JsonProperty(value="weight",required=true) int weight) {      this.name=name;      this.weight=weight;  }}public class Dog extends Animal {    private int barkVolume;    @JsonCreator    public Dog(String name,int weight, @JsonProperty(value="barkVolume",required=true) int barkVolume) {        super(name, weight);        this.barkVolume=barkVolume;    }}解串器應(yīng)該能夠從json字符串中推斷并實(shí)例化適當(dāng)?shù)淖宇?。我使用了一個(gè)自定義的反序列化器模塊，UniquePropertyPolymorphicDeserializer（來自https://gist.github.com/robinhowlett/ce45e575197060b8392d）。該模塊的配置如下：UniquePropertyPolymorphicDeserializer<Animal> deserializer =             new UniquePropertyPolymorphicDeserializer<Animal>(Animal.class);        deserializer.register("barkVolume", Dog.class);        SimpleModule module = new SimpleModule("UniquePropertyPolymorphicDeserializer");        module.addDeserializer(Animal.class, deserializer);        mapper.registerModule(module);該模塊向用戶詢問Animal的每個(gè)子類的唯一屬性。因此，當(dāng)反序列化程序找到具有barkVolume屬性的json字符串時(shí)，它知道應(yīng)該實(shí)例化Dog。但是，我對(duì)json屬性的規(guī)范存在疑問，因?yàn)樽宇惒荒軓母割愔薪o定的屬性繼承。在Dog類中，我必須再次指定“ name”和“ weight”是json屬性，即使在Animal類中已經(jīng)指定了這些屬性：public Dog(@JsonProperty(value="name") String name, @JsonProperty(value="weight",required=true) int weight, @JsonProperty(value="barkVolume",required=true) int barkVolume) {        super(name, weight);        this.barkVolume=barkVolume;    }否則，解串器將產(chǎn)生錯(cuò)誤：com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Invalid type definition for type `Animals.Dog`: Argument #0 has no property name, is not Injectable: can not use as Creator [constructor for Animals.Dog, annotations: {interface com.fasterxml.jackson.annotation.JsonCreator=@com.fasterxml.jackson.annotation.JsonCreator(mode=DEFAULT)}] at [Source: UNKNOWN; line: -1, column: -1]這個(gè)解決方案對(duì)我來說并不令人滿意：每次我們要?jiǎng)?chuàng)建Animal的新子類時(shí)，都必須在此類中指定name和weight為json屬性。