java - JsonView 序列化取决于某些条件/属性名称等

Question

我的一个类有 3 个相同类型的属性。现在我正在尝试将其序列化为 JSON，但其中一个属性需要以不同的方式序列化 - 基本上这些属性之一是“内部”，我只需要它的 id，其余属性必须完全序列化。

到目前为止我经历了什么:

@NoArgsConstructor @AllArgsConstructor @Data
public static class Id {
    @JsonView(View.IdOnly.class) private long id;
}

@NoArgsConstructor @AllArgsConstructor @Data
public static class Company extends Id {
    @JsonView(View.Tx.class) private String name;
    @JsonView(View.Tx.class) private String address;
}

@NoArgsConstructor @AllArgsConstructor @Data
public static class Transaction {
    @JsonView(View.Tx.class)     private Company from;
    @JsonView(View.Tx.class)     private Company to;
    @JsonView(View.IdOnly.class) private Company createdBy;
}

public static class View {
    public interface Tx extends IdOnly {}
    public interface IdOnly {}
}

并对其进行快速测试:

@Test
void test() throws JsonProcessingException {
    Company s = new Company("Source", "address_from");
    Company d = new Company("Destination", "address_to");
    final Transaction t = new Transaction(s, d, s);

    final ObjectMapper m = new ObjectMapper();
    System.out.println(m.writerWithDefaultPrettyPrinter().withView(View.Tx.class).writeValueAsString(t));
}

输出是:

{
  "from" : {
    "id" : 0,
    "name" : "Source",
    "address" : "address_from"
  },
  "to" : {
    "id" : 0,
    "name" : "Destination",
    "address" : "address_to"
  },
  "createdBy" : {
    "id" : 0,
    "name" : "Source",
    "address" : "address_from"
  }
}

现在，问题是，如何自定义 createBy 属性的序列化？我需要以下输出:

{
  "from" : {
    "id" : 0,
    "name" : "Source",
    "address" : "address_from"
  },
  "to" : {
    "id" : 0,
    "name" : "Destination",
    "address" : "address_to"
  },
  "createdBy" : {
    "id" : 0,
  }
}

Answer 1

哦，我认为答案非常简单:

1. 使用 @JsonSerialize(using = CS.class) 标记 createdBy 字段
2. 按如下方式实现自定义序列化器:

    public static class CS extends JsonSerializer<Company> {
        @Override
        public void serialize(Company company, JsonGenerator jgen, SerializerProvider serializerProvider) throws IOException {
            jgen.writeStartObject();
            jgen.writeNumberField("id", company.getId());
            jgen.writeEndObject();
        }
    }