java - 有没有办法从具有对象组合的 pojo 自动生成展平 pojo

Question

我需要将文档存储到 Elasticsearch 索引中，因此我定义了一个映射。我需要从我的 java 客户端向它提供看起来像 Compony 类的 pojo。它有很多重复的值。我可以使用对象组合模式来解决这个问题，但 Elasticsearch 无法处理这种结构，因此它需要扁平结构。

class Company {
    private String postalstreetName;
    private String postalHouseNumer;
    private String postalHouseLetter;
    private String postalHouseNumberAddition;
    private String postalZipCode;
    private String postalCity;
    private String postalCountry;

    private String visitorstreetName;
    private String visitorHouseNumer;
    private String visitorHouseLetter;
    private String visitorHouseNumberAddition;
    private String visitorZipCode;
    private String visitorCity;
    private String visitorCountry;

    private String establishmentstreetName;
    private String establishmentHouseNumer;
    private String establishmentHouseLetter;
    private String establishmentHouseNumberAddition;
    private String establishmentZipCode;
    private String establishmentCity;
    private String establishmentCountry;
}

我实际上想要像下面这样的 pojo，并以某种方式自动生成上面具有相同命名结构的 pojo。

class Address {
    private String streetName;
    private String houseNumer;
    private String houseLetter;
    private String houseNumberAddition;
    private String zipCode;
    private String city;
    private String country;
}

class Company {
    private Address postalAddress;
    private Address visitorAddress;
    private Address establishmentAddress;
}

有人知道这样的事情是否可能，从具有对象组合的 pojo 自动生成一个扁平化的 pojo，并为所有字段添加名称前缀？

Answer 1

我的问题得到了解决。 Elasticsearch 需要一个 json 对象，其结构与第一个示例中的结构相同。所以我所做的是将 @JsonUnwrapped 添加到带有前缀值的字段中，所以我的 Company 类如下所示:

class Company {
    @JsonUnwrapped(prefix = "postal")
    private Address postalAddress;
    @JsonUnwrapped(prefix = "visitor")
    private Address visitorAddress;
    @JsonUnwrapped(prefix = "Establishment")
    private Address establishmentAddress;
}

结果将是:

{
  "postalStreetName":"",
  "postalHouseNumer":"",
  "postalHouseLetter":"",
  "postalHouseNumberAddition":"",
  "postalCity":"",
  "postalCountry":"",
  "visitorStreetName":"",
  "visitorHouseNumer":"",
  "visitorHouseLetter":"",
  "visitorHouseNumberAddition":"",
  "visitorCity":"",
  "visitorCountry":"",
  "establishmentStreetName":"",
  "establishmentHouseNumer":"",
  "establishmentHouseLetter":"",
  "establishmentHouseNumberAddition":"",
  "establishmentCity":"",
  "establishmentCountry":""
}    

所以我不需要以某种方式神奇地创建这些 pojo，因为 jackson 可以创建我需要的 json 文件。