@JSONProperty嵌套字段映射问题

Question

{
  "success" : true,
  "message" : "ok",
  "product" : {
     "name : "food",
     "price" : 123
  }
}

public class RequestDTO {

   @JsonProperty("success")
   boolean success;

   @JsonProperty("message")
   boolean message;

   @JsonProperty("product.name")
   Stirng name;

   @JsonProperty("product.price")
   Long price;

}

我想映射到产品字段，而不创建product类

应该如何序列化和反序列化？

Answer 1

让我们首先编辑requestdto:

@JsonSerialize(using = Serializer.class)
public class RequestDTO {
    @JsonProperty("success")
    boolean success;

    @JsonProperty("message")
    boolean message;

    String name;

    Long price;

    @JsonProperty("product")
    private void unpackNestedProduct(Map<String,Object> product) {
        this.name = (String)product.get("name");
        this.price = Long.valueOf((Integer)product.get("price"));
    }

    @JsonProperty("message")
    private void unpackMessage(String messageStr) {
        this.message = messageStr.equalsIgnoreCase("ok");
    }
}

并添加序列化程序类：

public class Serializer extends StdSerializer<RequestDTO> {

    public Serializer() {
        this(null);
    }

    public Serializer(Class<RequestDTO> t) {
        super(t);
    }

    @Override
    public void serialize(RequestDTO value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
        jgen.writeStartObject();
        jgen.writeBooleanField("success", value.success);
        jgen.writeStringField("message", value.message ? "ok" : "PutYourNotOKValueHere");

        jgen.writeFieldName("product");
            jgen.writeStartObject();
            jgen.writeStringField("name", value.name);
            jgen.writeNumberField("price", value.price);
            jgen.writeEndObject();

        jgen.writeEndObject();
    }
}

然后我们可以做：

String json = "{\"success\": true, \"message\": \"ok\", \"product\":{ \"name\": \"food\", \"price\": 123}}";
ObjectMapper objectMapper = new ObjectMapper();

RequestDTO requestDTO = objectMapper.readValue(json, RequestDTO.class);
System.out.println("To Java object: "+ requestDTO);
System.out.println("Back to JSON: "+ objectMapper.writeValueAsString(requestDTO));

To Java object: RequestDTO(success=true, message=true, name=food, price=123)
Back to JSON: {"success":true,"message":"ok","product":{"name":"food","price":123}}

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