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
Related
I am trying to serialize a list of java Objects (POJO) into RecordIO format. I have seen this BeanIO (http://beanio.org/) but it seems to be outdated. Is there any other Java library that could be used or a different way to do this ?
Once list of objects is serialized it will be used to train a model with SageMaker.
Solving my own problem. I decided to use Apache Avro instead of BeanIO. Spark allow to serialize using Avro (c.f. Spark-Avro). This seems to work however it did not fit my use case has I was trying to serialize an array of numbers.
I want to parse JSON data from a RESTful service.
Unlike a SOAP-based service, where a service consumer can create stubs and skeleton from WSDL, in the case of the RESTful service, the service consumer gets a raw JSON string.
Since the service consumer does not have a Java object matching the JSON structure, we are not able to use the JSON to Java Mappers like GSON, Jackson etc.
One another way is to use parsers like JsonPath, minimal-json, etc which help traversing the JSON structure and read the data.
Is there any better way of reading JSON data?
The official docs for Jackson mention 3 different ways to parse a JSON doc from Java. The first 2 do not require "Java object matching the JSON structure". In Summary :
Streaming API (aka "Incremental parsing/generation") reads and writes JSON content as discrete events.
Tree Model provides a mutable in-memory tree representation of a JSON document. ObjectMapper can build trees that consist of JsonNode nodes.
Data Binding converts JSON to and from POJOs based either on property accessor conventions or annotations.
With simple data binding you convert to and from Java Maps, Lists, Strings, Numbers, Booleans and nulls
With full data binding you convert to and from any Java bean type (as well as "simple" types mentioned above)
Another option is to generate Java Beans from JSON documents. You mileage may vary and you may/probably will have to modify the generated files. There are at least 5 online tools for that purpose that you can try:
http://www.jsonschema2pojo.org/
http://pojo.sodhanalibrary.com/
https://timboudreau.com/blog/json/read
http://jsongen.byingtondesign.com/
http://json2java.azurewebsites.net/
There are also IDE plugins that you can use. For instance this one for Intellij https://plugins.jetbrains.com/idea/plugin/7678-jackson-generator-plugin
The GSON supports work without objects, too. Something as this:
JsonObject propertiesWrapper = new JsonParser().parse(responseContent).getAsJsonObject();
assertNotNull(propertiesWrapper);
propertiesWrapper = propertiesWrapper.getAsJsonObject("properties");
assertNotNull(propertiesWrapper);
JsonArray propertiesArray = propertiesWrapper.getAsJsonArray("property");
assertNotNull(propertiesArray);
assertTrue(propertiesArray.size()>0, "The list of properties should not be empty. ");
The problem is that the work this way is so inconvenient that it is really better to create objects instead.
Jackson has absolutely the same problems, and to greater extent - extremal inconvenient for direct json reading/creation. All its tutorials advice to use POJOs instead, too.
The only really convenient way is use Groovy. Groovy works as an envelope on Java, you can simply write Java code and use Groovy operators at need. And in JSON or XML reading and creation Groovy is incomparably more powerful that Java with all its libraries multiplied on each other! It is even much more convenient than already prepared by somebody else tree structure of ready POJOs.
So there is a nice library for VB6 JSON parsing. HERE
but i actually used one that built on the original and optimized. HERE
Essentially I'm using the parser to deserialize the json i get from a web service. I need to update some values, and resend to the server. Using the Collection/Dictionary objects made it very easy. But now, How do i take those objects and serialize them to a JSON string? is there a library for that?
thanks you for your help.
There are quite a few JSON parser/serializer/DOM classes written in VB6. Perhaps you might want to consider one of those instead. E.g.:
JsonBag, Another JSON Parser/Generator
In my GWT project I need to process json data retrieved from a database via PHP. I have seen the Google examples using JavaScriptObject overlay classes. What I don't understand is why this seems to be the prefered method of processing the json data. Why shouldn't I use all native Java code to pull in the data?
Think about it the other way around: what does it mean to use POJOs? (or native Java classes as you name them)
You have to:
parse the JSON into some Java-accessible structure (e.g. com.google.gwt.json.client.JSONObject, or elemental.json.JsonObject)
create POJOs
fill the POJOs with the data from the parsed JSON structure
now you can forget the parsed JSON structure from step 1
On the other hand, with JavaScriptObject, you use JsonUtil.safeEval and TA-DA! you get your JSON parsed right into a typed Java object!
Now, to deal with JSON, there's also AutoBeans.
Choose your poison.
Has anyone managed to parse and write JSON in a task in Ant?
I need to parse a json file, modify it and then write it back on disk. I managed to parse it using the rhino engine from JDK 6 but i'm stuck because I don't know how to serialize it back to disk.
It seemes I need a JSON serializer, rhino does not apparently include one.
Recent versions of Rhino should have a JSON object: see this bug that was resolved as fixed in 2010, and the actual class is called NativeJSON and has a stringify method that should let you retrieve a JSON string.
JSON.stringify is available with Rhino 1.7R3 onwards as part of the ECMAScript 5 work.
See: https://developer.mozilla.org/En/New_in_Rhino_1.7R3