I am having trouble saving a JSONObject to a MongoDB database using the MongoDB plugin.
I receive the message:
Can't find a codec for class org.codehaus.groovy.grails.web.json.JSONObject..
This is very frustrating because I am using the JSON parser to load JSON data but can't persist this JSON data to the MongoDb which should be straightforward.
Is there a built in way to convert a JSONOBject to a normal Map? I've tried casting it using asType( Map ), ( Map ), and even using toString() and thent rying to convert back from string to object. I've seen that other vanilla Java questions involve using Jackson but I'm hoping there is a Groovier way to do this rather than importing a whole new library for just two lines of code.
This is what I'm doing for now:
Converting the JSONObject to a string and then using com.mongodb.util.JSON.parse() to convert that string to a DBObject that Mongo can use.
It's not the best but it works for now.
I'm not going to accept this answer because I don't think it's the right answer.
Not saying this is the correct answer, but I was able to convert the JSONObject to a HashMap. For my situation I had a Domain object with an ArrayList (converted from JSONArray by a previous JSONTranslationService) and I was able to convert each of the internal JSONObjects using something like this:
static final UNMARSHAL = { thing ->
thing.objects.collect {
it as Hashmap
}
}
I'm only experiencing this issue after an upgrade from mongodb:3.0.2 to 6.1.2 to support MongoDB 3.4. Are you also running this version of the plugin? If so, I think it's fair to say that there's either a bug in the plugin (I'm already aware of one) or something changed with the default behavior and wasn't documented.
Related
I was expecting a JSON string while testing an API using Postman, but instead got this:
{city=Shanghai, work=112-454-7895, fax=788-899-7899}
Obviously I cannot put that into Google and ask what format is it, hence I am asking it here. Postman also says it is a 'bad string'.
I have never seen the above data serialization format. If someone can point the format out to me I would be able to find and use a converter. Additional suggestion with converting it to POJO or JSON are welcome as well.
I figured out that the above format is a stringified version of a HashMap<String, String>, and that there is no direct way to convert it into JSON/POJO. Converting it into json string requires additional work but is fairly straightforward.
I need to deserialize some JSON objects. I tried to use Tiny-json library, but it's too slow. I tried to use Newtonsoft.Json, but it fails in webplayer with this error:
MissingMethodException: Method not found: 'System.Collections.ObjectModel.KeyedCollection.
What JSON parser do you recommend?
You can try one of these open source solutions:
https://github.com/jacobdufault/fullserializer
https://github.com/mtschoen/JSONObject (https://www.assetstore.unity3d.com/en/#!/content/710) I am using this one most of the times, it's versbose but does its job well, not sure about performance however
Or go with paid ones:
https://www.assetstore.unity3d.com/en/#!/content/11347
Unity 5.3 added Native support of Json Serializer. It is faster than others.
JsonUtility.ToJson to convert a class to Json.
JsonUtility.FromJson to convert Json back to class.
For complete example and information regarding json arrays, see
Serialize and Deserialize Json and Json Array in Unity
This question already has answers here:
Writing Custom Kafka Serializer
(3 answers)
Closed 2 years ago.
I am new to Kafka, Serialization and JSON
WHat I want is the producer to send a JSON file via kafka and the consumer to consume and work with the JSON file in its original file form.
I was able to get it so JSON is converter to a string and sent via a String Serializer and then the consumer would parse the String and recreate a JSON object but I am worried that this isnt efficient or the correct method (might lose the field types for JSON)
So I looked into making a JSON serializer and setting that in my producer's configurations.
I used the JsonEncoder here : Kafka: writing custom serializer
But when I try to run my producer now, it seems that in the toBytes function of the encoder the try block is never returning anything like i want it to
try {
bytes = objectMapper.writeValueAsString(object).getBytes();
} catch (JsonProcessingException e) {
logger.error(String.format("Json processing failed for object: %s", object.getClass().getName()), e);
}
Seems objectMapper.writeValueAsString(object).getBytes(); takes my JSON obj ({"name":"Kate","age":25})and converts it to nothing,
this is my producer's run function
List<KeyedMessage<String,JSONObject>> msgList=new ArrayList<KeyedMessage<String,JSONObject>>();
JSONObject record = new JSONObject();
record.put("name", "Kate");
record.put("age", 25);
msgList.add(new KeyedMessage<String, JSONObject>(topic, record));
producer.send(msgList);
What am I missing? Would my original method(convert to string and send and then rebuild the JSON obj) be okay? or just not the correct way to go?
THanks!
Hmm, why are you afraid that a serialize/deserialize step would cause data loss?
One option you have is to use the Kafka JSON serializer that's included in Confluent's Schema Registry, which is free and open source software (disclaimer: I work at Confluent). Its test suite provides a few examples to get you started, and further details are described at serializers and formatters. The benefit of this JSON serializer and the schema registry itself is that they provide transparent integration with producer and consumer clients for Kafka. Apart from JSON there's also support for Apache Avro if you need that.
IMHO this setup is one of the best options in terms of developer convenience and ease of use when talking to Kafka in JSON -- but of course YMMV!
I would suggest to convert your event string which is JSON to byte array like:
byte[] eventBody = event.getBody();
This will increase your performance and Kafka Consumer also provides JSON parser which will help you to get your JSON back.
Please let me know if any further information required.
There's a bit of work to set the stage, so please bear with me...
I'm using knockout to databind a rather deeply nested data structure. When I retrieve the data from the database (from MongoDB using the Mongo C# Driver) there are nested properties (of type List<T>) that aren't populated and are returned as null. I'm using the ServiceStack.Text .ToJson extension method to serialize this data structure to JSON that gets passed to the client for knockoutMapper to convert into my observable viewModel. All goes well, except for the List<T> properties that were null on the server. Since they arrive at the client with a null value, knockoutMapper just makes them observables instead of observableArrays. Now for the question... Is there any way to tell ServiceStack that I want any property of type List<T> that is empty to be serialized as an empty array? I've dug through the JsConfig object to find a setting that looks like it might help but haven't had any luck. Am I missing something in JsConfig or is this something I should be doing in knockoutMapping on the client?
EDIT: Just a note - this is a side project where I'm learning 3-4 new technologies and I have come to see how absurd it is to retrieve JSON from Mongo, use the C# driver to convert this to a POCO to work with it on the server, then to use serviceStack to serialize the POCO as JSON. I plan on changing this with a straight through shot of just JSON, but this is a learning process for me.
I'm in the process of upgrading a grails plugin from 1.3.4 to grails 2.1.1. After upgrading I now have an integration test that fails that was not failing before. It fails on using the "as JSON" (grails.converters.JSON).
#Test
public void testConvertCollectionOfEnvironmentSettingsToJSON() {
EnvironmentSetting setting = configurationService.getEnvironmentSetting('ENFORCE_SCHEMA_INSTANCE_RULE')
def jsonSetting = setting as JSON //exception thrown here
def s = jsonSetting as String
assertNotNull jsonSetting
}
The exception and stacktrace:
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'com.company.ipsvc.configuration.domain.EnvironmentSettingAllRevs#48c12420' with class 'com.company.ipsvc.configuration.domain.EnvironmentSettingAllRevs' to class 'grails.converters.JSON'
at com.company.ipsvc.configuration.converter.json.basic.BasicEnvironmentSettingJSONIntegrationTests.testConvertCollectionOfEnvironmentSettingsToJSON(BasicEnvironmentSettingJSONIntegrationTests.groovy:28)
I am able to use encodeAsJSON() successfully. I also have the same issue with as XML.
I think converters (as JSON syntax) will only work on domain objects and collections by default.
To convert arbitrary objects you should use the encodeAsJSON() converter, I believe. Or use an object marshaller, where you tell the converter how to deal with your object.
The docs aren't very clear on this though..
See:
http://grails.org/Converters+Reference (object marshalling section at bottom)
http://grails.org/doc/latest/ref/Plug-ins/codecs.html
But I note that http://grails.org/doc/latest/api/grails/converters/JSON.html#JSON%28java.lang.Object%29 says that the object converts POGOs.. Maybe it means if you have a marshaller?
I did find this reference too:
Notice that the ‘as’ operator is not overloaded for plain objects ...
Domain objects can use the ‘as’ operator to cast an object to JSON, the same as a collection. So unlike POGOs, where they must be massaged into a list or have encodeAsJSON explictly called ...
http://manbuildswebsite.com/2010/02/08/rendering-json-in-grails-part-2-plain-old-groovy-objects-and-domain-objects/
Which seems to describe the situation.
For non-Domain objects, we found that this would crop up when running tests... the solution for us was to use new JSON:
render new JSON( obj )
This would allow the test to work, and the code does the same thing (essentially)
Ran into a similar issue that broke unit test using grails 2.2.1 . At issue was a straight obj as JSON conversion attempt. But this was interpreted as type casting instead.
The workaround is to stuff your obj to be converted into a map like this [data:obj] as JSON