I am getting a service response from Azure API in JSON format, but I need to transform it into Java class object format. Please suggest the simplest way to transform
There is website on which you can put json response and select the language in which you want to create classes.
This is simplest way to transform -
https://app.quicktype.io/
You can use com.fasterxml.jackson.databind.ObjectMapper
Exemple :
ObjectMapper mapper = new ObjectMapper().configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
UserType user= mapper.readValue("your_Json", UserType.class);
Related
I am trying to parse a json received from server in different custom objects, all implement single interface. My Json looks like
I have created classes MyFile, Display, PlayList and Manager. All implement EntityIFace.
First I created a wrapper class with one element of type List and tried restTemplate.exchange but list was null.
Then I decided to read json in String and parse it.
ResponseEntity responseEntity = restTemplate.getForEntity(baseUrl, String.class);
How can I read this json String into List of EntityIFace. Is there are way I can implement custom ObjectMapper? Or any other way to read this structure?
Thanks in Advance
Found a solution ..
I am reading json in String and parsing it using code below
ObjectMapper mapper = new ObjectMapper();
JsonNode jsonNode = mapper.readTree(json);
JsonNode arrayNode = jsonNode.get("entities");
and Then getting entities using jsonNode.get() method.
a:34:
{
s:2:\"id\";
i:14;
s:10:\"created_at\";
s:19:\"2017-02-20 17:09:01\";
s:10:\"updated_at\";
s:19:\"2017-11-01 08:30:43\";
s:11:\"id\";i:3;s:7:\"username\";
}
these is format i am getting, how to deserialize.
Any help thankyou
The google has a very good library for JSON serialization/deserialization, named
Gson.
If you have a json string and you want to deserialize, you can do it simply by calling:
new Gson().fromJson(yourJsonString, Model.class);
where Model is the model class, where you can map your json string. If you check the library documentation, you can find more interesting things.
What is the way to generate a Java object with get and set methods?
You should write a java bean with properties maching the JSON key's, from that point since you already have a reader its a simple as
YourObject obj = gson.fromJson(br, YourObject.class);
UPDATE
With respect to your comment, when you don't want or can't create a bean it usually boils down to parsing JSON to map. GSON (afaik) doesn't have a built-in for this, but its not hard to build a method that will traverse GSON's objects. You have an example in this blog
http://itsmyviewofthings.blogspot.it/2013/04/jsonconverter-code-that-converts-json.html
As you seem to be open to alternatives, take a look at Jackson as well (the two libs are the de-facto standard in JAVA).
With jackson you don't have to create a bean to support deserialization, e.g.
String json = "{\"id\":\"masterslave\"}";
Map<String,String> map = new HashMap<String,String>();
ObjectMapper mapper = new ObjectMapper();
//convert JSON string to Map
map = mapper.readValue(json,
new TypeReference<HashMap<String,String>>(){});
http://www.jsonschema2pojo.org/
That link helps generate the Java object format based on the GSON you feed in. Just make sure you set the settings exactly as you need it. As always, it's not a good idea to just copy-paste generated code, but it might be of help.
I've been looking at the couchbase-java-client project and wondering whether it's possible to use it inside of a dropwizard project.
It seems like it'd be a natural fit, because couchbase is basically a JSON database, but the java client doesn't seem to be compatible with Jackson. As far as I can tell, the couchbase client library includes its own internal implementation of a JSON library that's incompatible with all the other java JSON libs out there, which is really weird.
I found a JacksonTransformers class that looked promising at first. But upon closer inspection, the library is using a shaded version of Jackson (with a rewritten package of com.couchbase.client.deps.com.fasterxml.jackson.core).
Anyhow, since dropwizard uses Jackson and Jersey for marshalling JSON documents through the REST API, what's the least-friction way of using the couchbase-java-client library? Is it even possible in this case?
It is definitely possible to use Couchbase with Dropwizard. The client SDK provides JSON manipulation objects for the developer's convenience but it also allows for delegating JSON processing to a library like Jackson or GSON.
Take a look at the RawJsonDocument class here.
Basically, you can use a Stringified JSON (coming out of any framework) to create one of those objects and the client SDK will understand it as a JSON document for any operation i.e.:
String content = "{\"hello\": \"couchbase\", \"active\": true}";
bucket.upsert(RawJsonDocument.create("rawJsonDoc", content));
It should be possible to make this work.
Client requests to dw server for Resource Person.
DW server requests to couchebase, gets a Pojo back representing Person or JSON representing person.
If it's JSON, create a POJO with Jackson annotations in DW and return that to client
If it's a special couchebase pojo, map that to a Jackson pojo and return to to client
A solution based on #CamiloCrespo answer:
public static Document<String> toDocument(String id, Object value,
ObjectMapper mapper) throws JsonProcessingException {
return RawJsonDocument.create(id, mapper.writeValueAsString(value));
}
Keep in mind, that you can't use a simply maper, like ObjectMapper mapper = new ObjectMapper(), with Dropwizard.
You can get it from Environment#getObjectMapper() in the Application#run() method, or use Jackson.newObjectMapper() for tests.
An example of using:
ObjectMapper mapper = Jackson.newObjectMapper();
User user = User.createByLoginAndName("login", "name");
bucket.insert(toDocument("123", user, mapper));
I am working on a GWT application.
I want to convert a hashMap to JSON String and send it to GWT server
My HashMap is like HashMap<String, CustomProperties)
CustomProperties is the class with different parameters. This HashMap is property of file .
I want to uplaod a file with these properties.
What I am going to do : Attach the json Sting to hidden field and send it with the file through the formPanel.
But I dont know how to do Hashmap to JSON String.
Can anyone guide me in this regard ?
Consider using the GWT AutoBean framework for serializing to and from JSON.
JohnS' answer makes sense.
However, there is a related and a long ago answered question: GWT HashMap to/from JSON for details.
You could give Jackson a try.
http://wiki.fasterxml.com/JacksonInFiveMinutes
ObjectMapper mapper = new ObjectMapper();
mapper.writeValue(outputStream, yourMap);
yourMapinJson=outputStream.toString();