Hi I am new to Java and not sure how to proceed (kindly ignore any typos or my language). Can somebody help me out (just the Idea/how to proceed, dont need any sample code). I am trying to create a Restful Json webservice (using Spring MVC).
The webservice that I am trying to create is kind of a wrapper for an existing XML based restful webservice.
The Idea is to have one common platform, since all other existing services are exposed as as JSON services.
My job is to fetch the XML transform it into a Json, but the tricky part is The Json schema is a superset of the XML schema (I mean it contains more elements that get filled with some default values).
Please let me know if you need more info.
Thanks in advance.
One way to do it would be to use Jaxb to transform the the incoming XML to Java Objects. Build your Jaxb objects in a way that it contains all the elements, the one with default values and the elements in the incoming XML.
Ones the XMl is converted into Jaxb you can use org.springframework.http.converter.json.MappingJacksonHttpMessageConverter message converter to convert your Jaxb object to Json string.
Related
Coming from this question: Conversion of XML Schema to JSON array list in Biztalk
We have the same situation: Our XML needs to be converted to JSON and we have child objects which can occur one or multiple times which must always result in a JSON array.
The problem is that we are not able to set a target namespace because our schema is generated by SAP (IDoc).
Are there other options to do the serialization? I would like to avoid a custom implementation for JSON serialization.
Create an internal BizTalk schema with a target namespace and map the SAP payload to that.
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.
I am looking for either guidance or a good example where I can map data coming from rest services to JSON "type" object which can then be used in a number of different react components.
The JSON Object will be used to map data from a few different rest services, which essentially hold very similar data which makes it better to use one object and then to bind the data to the respective React Components.
I am fairly new to React.JS and I have googled around to find a data mapper to JSON from Rest Service example.
Can anyone help?
You typically don't have to do too much, at least on the front end side. As long as the REST endpoint can return JSON responses you'll be fine. Just make sure you set the appropriate Content-Type headers in the request. Note that setting the header doesn't guarantee a JSON response, the server has to be able to send it in that format.
If you're creating the REST service yourself, you have many options. If you're using node, you can simply return a javascript object. If you're using some other language like Java, C#, etc., they come with libraries that can serialize objects into JSON for you. I use JSON.net when working with C#. In these cases, because the data will be returned as a string, you'll just need to JSON.parse() it upon receiving it and then set it to the appropriate React component's state.
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.