如何将 json object 反序列化为扁平格式直接字段？

Question

我有以下结构：

public class User {
    private Account account;
    //constuctors, getters and setters
}

public class Account {
    private String id;
    private String description;
    //constructor, getters and setters
}

当我执行请求时，我需要创建以下 JSON 结构：

{
    "account": 
    { 
        "id": "1",
        "description": "Some description"
    }
}

但我想以简短的方式指定此信息并以下列方式忽略（左'null'）'description'字段：

{
     "account": "1" // I want to set directly the id field in the account object.
}

我该怎么做？ 我尝试@JsonCreator注释和@JsonUnwrapped但没有结果。

Answer 1

您可以使用自定义反序列化器

public class AccountFromIdDeserializer extends StdDeserializer<Account> {
  public AccountFromIdDeserializer() { this(null);}
  protected AccountFromIdDeserializer(Class<Account> type) { super(type);}

  @Override
  public Account deserialize(JsonParser parser, DeserializationContext context)
  throws IOException, JsonProcessingException {
    Account account = new Account();
    account.setId(parser.getValueAsString());
    return account;
  }
}

并使用@JsonDeserialize在User的account节点上使用

   public class User {
      @JsonDeserialize(using = AccountFromIdDeserializer.class)
      private Account account;
      //constuctors, getters and setters
   }

Answer 2

最后我使用了@JsonCreator注解并创建了两个构造函数：

@JsonCreator
public Account(@JsonProperty("id") String id, @JsonProperty("description") String description) {
    this.id = id;
    this.description = description;
}

@JsonCreator
public Account(String id) {
     this.id = id;
}