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Can you also share reproducible failing example? Since we already have working example in |
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3 replies
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FYI, there is #3125, in case it helps. Seems like mapper is trying to deserialize
If you can provide this, maybe I can look into it. 👍🏼👍🏼 |
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Hi @JooHyukKim I made a reproducible example: Demopublic class JacksonInjectDemoV2 {
public static void main(String[] args) throws JsonProcessingException {
DeezerContext context = new DeezerContext();
TypeReference<Page<Track>> pageTypeReference = new TypeReference<Page<Track>>() {
};
Page<Track> page = new PagingMethod<>(context, "/artist/27/top", pageTypeReference).execute();
System.out.println(page);
page = page.getNext().execute();
System.out.println(page);
}
public interface HttpClient {
String get(String url, Map<String, String> queryParams);
}
public static class MockHttpClient implements HttpClient {
private int index = 5;
@Override
public String get(String url, Map<String, String> queryParams) {
String next = url + "?index=" + index;
index += 5;
return "{\"data\":[],\"next\":\"" + next + "\"}";
}
}
public static class DeezerContext {
private HttpClient httpClient;
private ObjectMapper objectMapper;
private String apiHost;
public DeezerContext() {
this(new MockHttpClient(), new ObjectMapper(), "https://api.deezer.com");
this.objectMapper.setInjectableValues(new InjectableValues.Std().addValue(
DeezerContext.class,
this
));
}
public DeezerContext(HttpClient httpClient, ObjectMapper objectMapper, String apiHost) {
this.httpClient = httpClient;
this.objectMapper = objectMapper;
this.apiHost = apiHost;
}
public HttpClient getHttpClient() {
return httpClient;
}
public void setHttpClient(HttpClient httpClient) {
this.httpClient = httpClient;
}
public ObjectMapper getObjectMapper() {
return objectMapper;
}
public void setObjectMapper(ObjectMapper objectMapper) {
this.objectMapper = objectMapper;
}
public String getApiHost() {
return apiHost;
}
public void setApiHost(String apiHost) {
this.apiHost = apiHost;
}
}
public interface Pageable {
}
public static class Track implements Pageable {
}
public static class Page<T extends Pageable> {
@JsonProperty("data")
private List<T> data;
@JsonProperty("next")
@JsonDeserialize(using = PagingMethodDeserializer.class)
private PagingMethod<T> next;
public Page() {
}
public Page(List<T> data, PagingMethod<T> next) {
this.data = data;
this.next = next;
}
public List<T> getData() {
return data;
}
public void setData(List<T> data) {
this.data = data;
}
public PagingMethod<T> getNext() {
return next;
}
public void setNext(PagingMethod<T> next) {
this.next = next;
}
@Override
public String toString() {
return "Page{" +
"data=" + data +
", next=" + next +
'}';
}
}
public static abstract class Method<T> {
@JacksonInject
private DeezerContext deezerContext;
@JsonProperty("path")
private String path;
@JacksonInject
private TypeReference<T> resultType;
public Method(DeezerContext deezerContext, String path, TypeReference<T> resultType) {
this.deezerContext = deezerContext;
this.path = path;
this.resultType = resultType;
}
public abstract T execute() throws JsonProcessingException;
@Override
public String toString() {
return "Method{" +
"deezerContext=" + deezerContext +
", path='" + path + '\'' +
", resultType=" + resultType +
'}';
}
public DeezerContext getDeezerContext() {
return deezerContext;
}
public String getPath() {
return path;
}
public TypeReference<T> getResultType() {
return resultType;
}
}
public static class GetMethod<T> extends Method<T> {
public GetMethod(DeezerContext deezerContext, String path, TypeReference<T> resultType) {
super(deezerContext, path, resultType);
}
@Override
public T execute() throws JsonProcessingException {
DeezerContext context = getDeezerContext();
String rawResponse = context.getHttpClient().get(context.getApiHost() + getPath(), getQueryParams());
ObjectMapper mapper = context.getObjectMapper();
JsonNode jsonResult = mapper.readTree(rawResponse);
// validate jsonResult
return mapper.treeToValue(jsonResult, getResultType());
}
protected Map<String, String> getQueryParams() {
return new HashMap<>();
}
}
public static class PagingMethod<T extends Pageable> extends GetMethod<Page<T>> {
@JsonProperty("index")
private Integer index;
@JsonCreator
public PagingMethod(@JacksonInject DeezerContext deezerContext, @JsonProperty("path") String path, @JacksonInject TypeReference<Page<T>> resultType) {
super(deezerContext, path, resultType);
}
@Override
protected Map<String, String> getQueryParams() {
Map<String, String> queryParams = super.getQueryParams();
if (index != null) {
queryParams.put("index", index.toString());
}
return queryParams;
}
public Integer getIndex() {
return index;
}
public void setIndex(Integer index) {
this.index = index;
}
@Override
public String toString() {
return "PagingMethod{" +
"index=" + index +
"} " + super.toString();
}
}
public static class PagingMethodDeserializer<T extends Pageable> extends StdDeserializer<PagingMethod<T>> implements ContextualDeserializer {
private ObjectMapper objectMapper;
public PagingMethodDeserializer() {
this(null, null);
}
protected PagingMethodDeserializer(ObjectMapper objectMapper, JavaType valueType) {
super(valueType);
this.objectMapper = objectMapper;
}
@Override
public PagingMethod<T> deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
URL url = new URL(p.getText());
Map<String, String> dto = new HashMap<>();
dto.put("path", url.getPath());
for (String queryParam : url.getQuery().split("&")) {
String[] keyVal = queryParam.split("=");
dto.put(keyVal[0], keyVal[1]);
}
return objectMapper.convertValue(dto, getValueType());
}
@Override
public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property) throws JsonMappingException {
DeezerContext context = (DeezerContext) ctxt.findInjectableValue(DeezerContext.class.getName(), null, null);
ObjectMapper mapper = context.getObjectMapper();
JavaType propertyType = property.getType();
InjectableValues.Std injectableValues = (InjectableValues.Std) mapper.getInjectableValues();
injectableValues.addValue(TypeReference.class, new TypeReference<T>() {
@Override
public Type getType() {
return propertyType.getSuperClass().containedType(0);
}
});
return new PagingMethodDeserializer<>(mapper, propertyType);
}
}
}Output |
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I found that if I annotate Output |
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I'm writing a specific service that needs to be deserialized by
ObjectMapper, and it must store the sameObjectMapperas its field.I was trying to write a small demo, but it works perfectly:
Output
The problem occurs when I try do the same in a real project.
Project link
The code flow is the following:
PagingMethod<Tracks>instance. This instance hasDeezerContextthat holdsObjectMapper.execute().Page<Track>.{ "data": [], // array containing 5 tracks "total": 100, // total tracks count "next": "https://api.deezer.com/artist/25/top?index=5" // API to get the next 5 tracks }nextwill be converted to newPagingMethod<Tracks>instance, and it will be holding the sameDeezerContext. Deserialiazition goes viaio.github.yvasyliev.deezer.json.PagingMethodDeserializerV2.The code is safe to run locally, no configuration or tokens required. Only Lombok annotation processing must be enabled.
If I try to run
io.github.yvasyliev.deezer.Main#main, I'll get an exception.Output
As I understand from the logs, mapper for some reason tries to create a JSON representation of
DeezerContext#objectMapper, althoughMethod#contextis annotated with@JacksonInject.As per docs, it's an "unusual" behavior.
Could you please suggest a proper way to inject
DeezerContext?Beta Was this translation helpful? Give feedback.
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