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The JSON-lib is a Java library for serializing and de-serializing java beans, maps, arrays, and collections in JSON format. We can add elements to the JSON object using the element() method of JSONObject class. We need to download all the dependent jars like json-lib.jar, ezmorph.jar, commons-lang.jar, commons-collections.jar, commons-beanutils.jar, and commons-logging.jar and can import net.sf.json package in our java program to execute it.Syntaxpublic JSONObject element(String key, Object value) - put a key/value pair in the JSONObject Exampleimport java.util.Arrays; import net.sf.json.JSONObject; public class JsonAddElementTest { public static void main(String[] args) { JSONObject jsonObj = new JSONObject() .element("name", "Raja ... Read More
The net.sf.json.JSONArray is an ordered sequence of values. Its external text form is a string wrapped in square brackets with commas separating the values and an internal form is an object having get() and opt() methods for accessing the values by index, and element() method for adding or replacing values. The values can be any of these types like Boolean, JSONArray, JSONObject, Number, String and JSONNull object.We can convert a collection(List) to JSON array in the below exampleExampleimport java.util.*; import net.sf.json.JSONArray; import net.sf.json.JSONSerializer; public class ConvertCollectionToJsonArrayTest { public static void main(String[] args) { List strList = Arrays.asList("India", "Australia", "England", ... Read More
The ExclusionStrategy interface can be used to exclude any field during serialization and deserialization. We can provide a custom implementation of the ExclusionStrategy interface and need to register it with GsonBuilder using the setExclusionStrategies() method. It configures Gson to apply a set of exclusion strategies during serialization and deserialization.Syntaxpublic GsonBuilder setExclusionStrategies(ExclusionStrategy... strategies)Exampleimport com.google.gson.*; import com.google.gson.ExclusionStrategy; import com.google.gson.FieldAttributes; public class ExclusionStrategyTest { public static void main(String args[]) throws Exception { Gson gson = new GsonBuilder().setExclusionStrategies(new CustomExclusionStrategy()).create(); Person person = new Person(); person.setFirstName("Adithya"); person.setLastName("Sai"); person.setAddress("Hyderabad"); ... Read More
The JsonBuilderFactory interface is a factory to create JsonObjectBuilder instance and JsonObjectBuilder is a builder for creating JsonObject models from scratch. This interface initializes an empty JSON object model and provides methods to add name/value pairs to the object model and to return the resulting object. We can create a JsonObjectBuilder instance that can be used to build JsonObject using the createObjectBuilder() method.SyntaxJsonObjectBuilder createObjectBuilder()In the below example, We can update an existing JSON data with newly added data.Exampleimport java.io.*; import javax.json.*; public class UpdateExistingJsonTest { public static void main(String[] args) throws Exception { String jsonString = "{\"id\":\"115\", \"name\":\"Raja\", \"address\":[{\"area\":\"Madhapur\", \"city\":\"Hyderabad\"}]}"; ... Read More
JSON Schema is a specification for JSON based format for defining the structure of JSON data. The JsonSchema class can provide a contract for what JSON data is required for a given application and how to interact with it. The JsonSchema can define validation, documentation, hyperlink navigation, and interaction control of JSON data. We can generate the JSON schema using the generateSchema() method of JsonSchemaGenerator, this class wraps the JSON schema generation functionality.Syntaxpublic JsonSchema generateSchema(Class type) throws com.fasterxml.jackson.databind.JsonMappingExceptionExampleimport com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.module.jsonSchema.JsonSchema; import com.fasterxml.jackson.module.jsonSchema.JsonSchemaGenerator; import java.util.List; public class JSONSchemaTest { public static void main(String[] args) throws JsonProcessingException { ... Read More
This example demonstrates how do I check if a Bluetooth device is connected with android device.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.javaimport android.bluetooth.BluetoothDevice; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.os.Bundle; import android.widget.Toast; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ... Read More
This example demonstrates how do I get the free size of internal/external memory in android app.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.javaimport android.os.Bundle; import android.os.Environment; import android.os.StatFs; import android.util.Log; import android.widget.TextView; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { TextView textView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ... Read More
This example demonstrates how to do I in android.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.javaimport android.annotation.SuppressLint; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.util.Base64; import android.widget.ImageView; import java.io.ByteArrayOutputStream; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { ImageView imageView; @SuppressLint("WrongThread") @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ... Read More
This example demonstrates how do I play background music in android.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.javaimport android.content.Intent; import android.os.Bundle; import android.view.View; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } public void PlayBackgroundSound(View view) { Intent intent ... Read More
The Java Arrays are objects which store multiple variables of the same type, it holds primitive types and object references and an ArrayList can represent a resizable list of objects. We can add, remove, find, sort and replace elements using the list. A JsonArray can parse text from a string to produce a vector-like object. We can convert an array or ArrayList to JsonArray using the toJsonTree().getAsJsonArray() method of Gson class.Syntaxpublic JsonElement toJsonTree(java.lang.Object src)Exampleimport com.google.gson.*; import java.util.*; public class JavaArrayToJsonArrayTest { public static void main(String args[]) { String[][] strArray = {{"elem1-1", "elem1-2"}, {"elem2-1", "elem2-2"}}; ArrayList arrayList = ... Read More