I have a JestClient (elasticsearch) response that I'm trying to deserialize into an object. The object contains two DateTime fields, whereas in the response, they're strings, so I'm getting:
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 102 path $.createdTimeStamp
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:226) ~[gson-2.8.5.jar:?]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:131) ~[gson-2.8.5.jar:?]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:222) ~[gson-2.8.5.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:927) ~[gson-2.8.5.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:892) ~[gson-2.8.5.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:841) ~[gson-2.8.5.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:813) ~[gson-2.8.5.jar:?]
at io.searchbox.client.JestResult.createSourceObject(JestResult.java:271) ~[Jest-6.x.jar:?]
at io.searchbox.core.SearchResult.access$000(SearchResult.java:17) ~[Jest-6.x.jar:?]
at io.searchbox.core.SearchResult$Hit.<init>(SearchResult.java:288) ~[Jest-6.x.jar:?]
at io.searchbox.core.SearchResult.extractHit(SearchResult.java:163) ~[Jest-6.x.jar:?]
at io.searchbox.core.SearchResult.getHits(SearchResult.java:92) ~[Jest-6.x.jar:?]
at io.searchbox.core.SearchResult.getHits(SearchResult.java:73) ~[Jest-6.x.jar:?]
at io.searchbox.core.SearchResult.getHits(SearchResult.java:65) ~[Jest-6.x.jar:?]
at io.searchbox.core.SearchResult.getHits(SearchResult.java:61) ~[Jest-6.x.jar:?]
So, I have created a custom deserializer to solve this.. However, whatever I do, I keep getting the same error. Somehow it's not registering to use it?
public final class DateTimeConverter extends TypeAdapter<DateTime> {
#Override
public void write(JsonWriter jsonWriter, DateTime dateTime) throws IOException {
if (Objects.isNull(dateTime)) {
jsonWriter.nullValue();
return;
}
jsonWriter.value(dateTime.toString());
}
#Override
public DateTime read(JsonReader jsonReader) throws IOException {
System.out.println("This statement doesn't print, so I'm assuming this method isn't being used during parsing");
String dateTimeString = jsonReader.nextString();
return DateTime.parse(dateTimeString);
}
}
I'm also setting my typeAdapter when initializing my client:
public JestClient getElasticsearchJestClient(#NonNull final AWSCredentialsProvider awsCredentialsProvider, #NonNull final Regions region) {
Gson gson = new GsonBuilder().registerTypeAdapter(DateTime.class, new DateTimeConverter()).create();
AESClientFactory factory = new AESClientFactory(awsCredentialsProvider, region.getName());
factory.setHttpClientConfig(new HttpClientConfig.Builder(ENDPOINT)
.multiThreaded(true)
.gson(gson).build());
return factory.getObject();
}
And finally, the code where I'm trying to parse the response from jestclient:
List<SearchResult.Hit<MyObject, Void>> hits;
SearchResult result = elasticsearchAccessor.getElasticsearchRecords(search);
hits = result.getHits(MyObject.class);
final List<MyObject> objects = hits.stream()
.map((hit) -> hit.source)
.collect(Collectors.toList());
No matter what I try I keep getting the error above, I'm not even sure at this point what to investigate-- any ideas are appreciated, I'm not sure what else to try.
This implementation ended up being correct. The reason it wasn't working in my tests was because I needed to add the adapter to the Gson I was initializing:
private static final Gson GSON = new GsonBuilder().registerTypeAdapter(ZonedDateTime.class, new DateTimeConverter()).create();
Related
I have 2 services S1 and S2. Calling S2 using annotated Feign client(#FeignClient) from S1. The issue is, I am unable to get traceId in S2.
But when I try to call S2 using RestTemplate it works.
Any help will be appreciated
Edited:
I have find out the cause actually I am using Feign.Builder below is sample code which builds fiegn client.
#ConditionalOnProperty(name = "feign.hystrix.enabled")
public Feign.Builder feignHystrixBuilder() {
SetterFactory setterFactory = new SetterFactory() {
#Override
public HystrixCommand.Setter create(Target<?> target, Method method) {
String groupKey = target.name();
String commandKey = target.name();
return HystrixCommand.Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
.andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
}
};
return HystrixFeign.builder().setterFactory(setterFactory);
}
Actually due to above config.. SleuthFeignHystrixBuilder is not invoked.
I need to set HysterixCommandKey in my format.. thats why need above config.
How can it work with spring-sleuth ?
I have implemented Spring's BeanPostProcessor interface and then set 'setterFactory'. Refer to below sample code
#Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
if(bean instanceof HystrixFeign.Builder) {
((HystrixFeign.Builder)bean).setterFactory(new SetterFactory() {
#Override
public HystrixCommand.Setter create(Target<?> target, Method method) {
String groupKey = target.name();
String commandKey = target.name();
return HystrixCommand.Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
.andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
}
});
}
return BeanPostProcessor.super.postProcessAfterInitialization(bean, beanName);
}
I try to call my AWS Lambda function (serverless backend) with my Android mobile app client. The AWS lambda function returns an ArrayList of POJO objects (as JSON).
The problem is that the android client AWS Lambda(JSON)DataBinder does not deserialize to my ArrayList of POJOs. I get an ArrayList of LinkedTreeMap (see code at onPostExecute() below).
At the android client side I'm using Android AWS SDK: com.amazonaws:aws-android-sdk-core:2.6
Here is some code:
public void readSurveyList(String strUuid, int intLanguageID) {
// Create an instance of CognitoCachingCredentialsProvider
// You have to configure at least an AWS identity pool to get access to your lambda function
CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
this.getApplicationContext(),
IDENTITY_POOL_ID,
Regions.EU_CENTRAL_1);
LambdaInvokerFactory factory = LambdaInvokerFactory.builder()
.context(this.getApplicationContext())
.region(Regions.EU_CENTRAL_1)
.credentialsProvider(credentialsProvider)
.build();
// Create the Lambda proxy object with default Json data binder.
myInterface = factory.build(MyInterface.class);
//create a request object (depends on your lambda function)
SurveyListRequest surveyListRequest = new SurveyListRequest(strUuid, intLanguageID);
// Lambda function in async task with definiton of
// request object (-> SurveyListRequest)
// response object (-> ArrayList<SurveyListItem>>)
new AsyncTask<SurveyListRequest, Void, ArrayList<SurveyListItem>>() {
#Override
protected ArrayList<SurveyListItem> doInBackground(SurveyListRequest... params) {
try {
return myInterface.ReadSurveyList(params[0]);
} catch (LambdaFunctionException lfe) {
Log.e("TAG", String.format("echo method failed: error [%s], details [%s].", lfe.getMessage(), lfe.getDetails()));
return null;
}
}
#Override
protected void onPostExecute(ArrayList<SurveyListItem> surveyList) {
// PROBLEM: here i get a ArrayList of LinkedTreeMap
}
}.execute(surveyListRequest);
}
Here is the code of my lambda function Interface:
public interface MyInterface {
#LambdaFunction
ArrayList<SurveyListItem> ReadSurveyList (SurveyListRequest surveyListRequest);
}
I would expect to get a list of my POJO objects. I found a lot of discussions about Gson and ArrayList type and solutions based on TypeToken (e.g. Gson TypeToken with dynamic ArrayList item type). Maybe same problem ...
I found a solution using a custom LambdaDataBinder. I have specified the type of my POJO-class "SurveyListItem" in deserialize function. The Gson uses the TypeToken definition and converts the JSON string correct to the list of POJOs (in my case "SurveyListItem" objects).
Here is the sourcecode of MyLambdaDataBinder:
public class MyLambdaDataBinder implements LambdaDataBinder {
private final Gson gson;
Type mType;
//CUSTOMIZATION: pass typetoken via class constructor
public MyLambdaDataBinder(Type type) {
this.gson = new Gson();
mType = type;
}
#Override
public <T> T deserialize(byte[] content, Class<T> clazz) {
if (content == null) {
return null;
}
Reader reader = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(content)));
//CUSTOMIZATION: Original line of code: return gson.fromJson (reader, clazz);
return gson.fromJson(reader, mType);
}
#Override
public byte[] serialize(Object object) {
return gson.toJson(object).getBytes(StringUtils.UTF8);
}
}
Here is how to use the custom MyLambdaDataBinder. Use your POJO instead of "SurveyListItem":
myInterface = factory.build(LambdaInterface.class, new MyLambdaDataBinder(new TypeToken<ArrayList<SurveyListItem>>() {}.getType()));
I am using a library com.fasterxml.jackson library for JsonSchema,
I am creating an IntegerSchema object, when I set range for integer schema using below code:
main(){
IntegerSchema intSchema = new IntegerSchema();
// setMaximum accepts Double object
intSchema.setMaximum(new Double(102000000));
// setMaximum accepts Double object
intSchema.setMinimum(new Double(100));
printJsonSchema(intSchema);
}
public void printJsonSchema(JsonSchema schema){
ObjectMapper mapper = new ObjectMapper();
try {
logger.info(mapper.writeValueAsString(schema));
} catch (JsonProcessingException e) {
throw new IllegalStateException(e);
}
}
When I convert IntegerSchema to string using ObjectMapper getting below response:
{"type":"integer","maximum":1.02E8,"minimum":100.0}
maximum and minimum values are getting converted to scientific notation.
But I need output in non scientific notation as below:
{"type":"integer","maximum":102000000,"minimum":100}
I cannot change IntegerSchema class.
Please suggest how to get the required output without extending IntegerSchema class?
Thanks in advance
this is a java issue somewhat I believe. If you debug your program, your Double will always be displayed scientifically, so what we'll want is to force it into a String. This can be achieved in Java in multiple ways, and you can look it up here:
How to print double value without scientific notation using Java?
In terms of your specific question about Jackson, I've written up some code for you:
public class ObjectMapperTest {
public static void main(String[] args) throws JsonProcessingException {
IntegerSchema schema = new IntegerSchema();
schema.type = "Int";
schema.max = 10200000000d;
schema.min = 100d;
ObjectMapper m = new ObjectMapper();
System.out.println(m.writeValueAsString(schema));
}
public static class IntegerSchema {
#JsonProperty
String type;
#JsonProperty
double min;
#JsonProperty
#JsonSerialize(using=MyDoubleDesirializer.class)
double max;
}
public static class MyDoubleDesirializer extends JsonSerializer<Double> {
#Override
public void serialize(Double value, JsonGenerator gen, SerializerProvider serializers)
throws IOException, JsonProcessingException {
// TODO Auto-generated method stub
BigDecimal d = new BigDecimal(value);
gen.writeNumber(d.toPlainString());
}
}
}
The trick is to register a custom Serializer for your Double value. This way, you can control what you want.
I am using the BigDecimal value to create a String representation of your Double. The output then becomes (for the specific example):
{"type":"Int","min":100.0,"max":10200000000}
I hope that solves your problem.
Artur
Feature.WRITE_BIGDECIMAL_AS_PLAIN
set this for your Object Mapper
I know I am answering late, but something I faced may help other
While converting a BigDecimal I have faced below is working
mapper = mapper.setNodeFactory(JsonNodeFactory.withExactBigDecimals(true));
while this is not working for me
mapper.configure(JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN, true);
Update for Jakson 2.9.10:
Property WRITE_BIGDECIMAL_AS_PLAIN replaced to com.fasterxml.jackson.core.JsonGenerator. You could use:
mapper.enable(JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN);
If you are using ValueToTree then no need of any factory settings. only problem with ValueToTree is it is converting as TextNode (String Fromat), So if you have any logic based on ObjectNodes it will not work
You should use
mapper.configure(DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS, true);
To avoid scientific notation on floating numbers.
You can find an example below.
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS, true);
String test ="{\"doubleValue\" : 0.00001}";
try {
System.out.println(mapper.readTree(test).toPrettyString());
} catch (JsonProcessingException e) {
e.printStackTrace();
}
Output
{
"doubleValue" : 0.00001
}
A library is using Map to use some extra information. This map eventually is being converted a JSON object and I need to set request information to display for debugging purposes as this:
map.put("request", requestString);
I am considering to use Jackson specifically to create a JSON without quotes and want to set as requestString.
I am building necessary information regarding Request and building a Map including request headers, parameters, method etc.
Jackson is creating perfectly valid JSON with quotes but when I set this generated value inside map, It is displayed ugly because of having escaped quotes.
So Jackson is creating this:
{
method : "POST",
path : "/register"
}
When I set this in map, it turns to this:
{
method : \"POST\",
path : \"/register\"
}
Consider this as a huge map including all parameters and other information about request.
What I would like to want this:
{
method : POST,
path : /register
}
I know that this is not a valid JSON but I am using this as a String to a Map which is accepting String values.
public class UnQuotesSerializer extends NonTypedScalarSerializerBase<String>
{
public UnQuotesSerializer() { super(String.class); }
/**
* For Strings, both null and Empty String qualify for emptiness.
*/
#Override
public boolean isEmpty(String value) {
return (value == null) || (value.length() == 0);
}
#Override
public void serialize(String value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
jgen.writeRawValue(value);
}
#Override
public JsonNode getSchema(SerializerProvider provider, Type typeHint) {
return createSchemaNode("string", true);
}
#Override
public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint) throws JsonMappingException {
if (visitor != null) visitor.expectStringFormat(typeHint);
}
}
and
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule("UnQuote");
module.addSerializer(new UnQuotesSerializer());
objectMapper.configure(JsonGenerator.Feature.QUOTE_FIELD_NAMES, false);
objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_CONTROL_CHARS, true);
objectMapper.registerModule(module);
This is generating without quotes strings.
The following test passes (Jackson 2.5.0)
#Test
public void test() throws Exception {
ObjectMapper mapper = new ObjectMapper();
Map map = new HashMap();
map.put("method", "POST");
map.put("request", "/register");
String s = mapper.writeValueAsString(map);
Map map2 = mapper.readValue(s, Map.class);
Assert.assertEquals(map, map2);
}
so your pseudo JSON without quotes does not seem the way to go
I have the following code with a simple class and a method for writing and then reading:
ObjectMapper mapper = new ObjectMapper();
try{
DataStore testOut = new DataStore();
DataStore.Checklist ch1 = testOut.addChecklist();
ch1.SetTitle("Checklist1");
String output = mapper.writeValueAsString(testOut);
JsonNode rootNode = mapper.readValue(output, JsonNode.class);
Map<String,Object> userData = mapper.readValue(output, Map.class);
}
public class DataStore {
public static class Checklist
{
public Checklist()
{
}
private String _title;
public String GetTitle()
{
return _title;
}
public void SetTitle(String title)
{
_title = title;
}
}
//Checklists
private Vector<Checklist> _checklists = new Vector<Checklist>();
public Checklist addChecklist()
{
Checklist ch = new Checklist();
ch.SetTitle("New Checklist");
_checklists.add(ch);
return ch;
}
public Vector<Checklist> getChecklists()
{
return _checklists;
}
public void setChecklists(Vector<Checklist> checklists)
{
_checklists = checklists;
}
}
The line:
String output = mapper.writeValueAsString(testOut);
causes an exception that has had me baffled for hours and about to abandon using this at all.
Any hints are appreciated.
Here is the exception:
No serializer found for class DataStore$Checklist and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: DataStore["checklists"]->java.util.Vector[0])
There are multiple ways to do it, but I will start with what you are doing wrong: your naming of getter and setter method is wrong -- in Java one uses "camel-case", so you should be using "getTitle". Because of this, properties are not found.
Besides renaming methods to use Java-style names, there are alternatives:
You can use annotation JsonProperty("title") for GetTitle(), so that property is recognized
If you don't want the wrapper object, you could alternatively just add #JsonValue for GetTitle(), in which case value used for the whole object would be return value of that method.
The answer seems to be: You can't do that with Json. I've seen comments in the Gson tutorial as well, that state that some serialization just doesn't work. I downloaded XStream and spat it out with XML in a few minutes of work and a lot less construction around what I really wanted to persist. In the process, I was able to delete a lot of code.