JAVA-JSON Serialization & Deserialization Using JACKSON

Converting JSON String to MAP

try {
   ObjectMapper mapper = new ObjectMapper();
   String json = "{\"JSON\":{\"type\":\"ID\",\"value\":\"vvv\"},\"info\": \"Yes\"}";
   Map<String, Object> map = new HashMap<String, Object>();
   // convert JSON string to Map
   map = mapper.readValue(json, new TypeReference<Map<String, Object>>(){});
   System.out.println("CONVERTING JSON STRING TO MAP--="+map);

  } catch (JsonGenerationException e) {
   e.printStackTrace();
  } catch (JsonMappingException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }

Converting MAP to JSON String

ObjectMapper mapper2 = new ObjectMapper();
  Map<String, Object> carMap = new HashMap<String, Object>();
  carMap.put("car", "Audi");
  carMap.put("price", "30000");
  carMap.put("model", "2010");
  List<String> colors = new ArrayList<String>();
  colors.add("Grey");
  colors.add("White");
  colors.add("Black");
  carMap.put("colors", colors);
  try {
   String jsonString = new ObjectMapper().writeValueAsString(carMap);
   System.out.println("Convert Map to JSON String=="+jsonString);
  } catch (JsonProcessingException e) {
   e.printStackTrace();
  }

Converting MAP to JSON Object

try {
   JSONObject jsonObject = new JSONObject(carMap);
   System.out.println("Convert Map to JSON Object=="+jsonObject);
  } catch (Exception e) {
   e.printStackTrace();
  }

Converting JSON Object to MAP

try {
   String jsonjsonString = "{\"JSON\":{\"type\":\"ID\",\"value\":\"vvv\"},\"info\": \"Yes\"}";
   ObjectMapper mapper12 = new ObjectMapper();
   JsonNode jsonNode = mapper12.readTree(jsonjsonString);
   Map<String, Object> mapp = new HashMap<String, Object>();
   mapp = convertJSONObjectToMap(jsonNode);
   System.out.println("Convert JSON Object to Map =="+mapp);
  } catch (Exception e) {
   e.printStackTrace();
  }

Output :

Xamarin.Forms - Social Media Application

Hi there!

In this blog post, I have created a Android application using Xamarin Forms that will show a list of posts, comments of each post and the user profile of the author of the post. I have used the  JSON Placeholder service to get the required information.

The application consist of three main screens.

1. Posts List
2. Comments for a post
3. User Profile

The projects are seperately created for data retrieval and the entities (data model).When the application starts, it shows the posts list page. Data fetching happens automatically in the background.

The below video shows a walk through of the Mobile Application developed using Xamarin Forms.

The source code of this application will be shared soon!!!

Ashen Jayasinghe
Software Developer
DMS