在 spring 引导中反序列化 jackson

Question

我通过调用 RestTemplate

获得了两种类型的 json

{"results":[{"testing":{"name":"soham"}},{"testing":{"firstname":"john","lastname":"don"}}]}

现在我正在使用 JsonDeserializer 解析数据

public class CustomJacksonDeserialize extends JsonDeserializer<Activity> {
    @Override
    public Activity deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws
            IOException, NullPointerException {
        ObjectMapper objectMapper = new ObjectMapper();
        JsonNode actualObj = objectMapper.readTree(jsonParser.getValueAsString());

            return new Activity(actualObj.get("name").asText());
    }
}

这是我的 class

@JsonDeserialize(using = CustomJacksonDeserialize.class)
public class Activity {

    private String name;

    public Activity(String name) {
        this.name = name;
    }
}

现在我的问题是如何解析这个 json。@JsonDeserialize 对这个 case.Any 其他选项没有帮助吗？或者在这种情况下如何使用 @JsonDeserialize .

Answer 1

您可以这样修改 CustomJacksonDeserialize :

class CustomJacksonDeserialize extends JsonDeserializer<Activity> {
    @Override
    public Activity deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException,
            NullPointerException {

        JsonNode jsonNode = jsonParser.readValueAsTree();

        String name=jsonNode.get("results").get(0).get("testing").get("name").asText();

        return new Activity(name);
    }
}

第二种方法： 或者，如果您也可以使用对象映射器本身反序列化 JSON 这不需要 CustomJacksonDeserialize :

String jsonString = "{\"results\":[{\"testing\":{\"name\":\"soham\"}},{\"testing\":{\"firstname\":\"john\",\"lastname\":\"don\"}}]}";
    ObjectMapper objectMapper = new ObjectMapper();

JsonNode jsonNode = objectMapper.readTree(jsonString);
JsonNode resultNode=jsonNode.get("results");
String name = resultNode.get(0).get("testing").get("name").asText();

Activity activity=new Activity(name);

String firstName=  resultNode.get(1).get("testing").get("firstname").asText();
String lastName=  resultNode.get(1).get("testing").get("lastname").asText();

Activity2 activity2=new Activity2(firstName, lastName);

注意：我已经为给定的 JSON 提取了 name、firstname 和 lastname 的值，您可以修改此逻辑相应。

第三种方法： 在这里我可以遍历 JSON 数组并将创建两个活动的单独对象：

String jsonString = "{\"results\":[{\"testing\":{\"name\":\"soham\"}},{\"testing\":{\"firstname\":\"john\",\"lastname\":\"don\"}}]}";

        ObjectMapper objectMapper = new ObjectMapper();

        JsonNode jsonNode = objectMapper.readTree(jsonString);

        JsonNode resultNode = jsonNode.get("results");

        List<Activity> activityList1 = new ArrayList<Activity>();

        List<Activity2> activityList2 = new ArrayList<Activity2>();

        for (int i = 0; i < resultNode.size(); i++) {

            JsonNode testingNode = resultNode.get(i).get("testing");

            if (testingNode.has("name")) {
                String name = testingNode.get("name").asText();

                Activity activity = new Activity(name);
                activityList1.add(activity);

            }

            if (testingNode.has("firstname")) {
                String firstName = testingNode.get("firstname").asText();
                String lastName = testingNode.get("lastname").asText();

                Activity2 activity2 = new Activity2(firstName, lastName);
                activityList2.add(activity2);

            }

        }

在 spring 引导中反序列化 jackson

Deserialize jackson in spring boot

java

json

jackson

spring-boot