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Programming Articles
Page 2321 of 2547
How can we decode a JSON object in Java?
A JSON is a lightweight, text-based and language-independent data exchange format. A JSON can represent two structured types like objects and arrays. We can decode a JSON object using JSONObject and JSONArray from json.simple API. A JSONObject works as a java.util.Map whereas JSONArray works as a java.util.List.In the below example, we can decode a JSON object.Exampleimport org.json.simple.*; import org.json.simple.parser.*; public class JSONDecodingTest { public static void main(String[] args) { JSONParser parser = new JSONParser(); String str = "[ 0 , {"1" : { "2" : ...
Read MoreHow can we encode a JSON object in Java?
A JSONObject is a subclass of java.util.HashMap where no order is provided. We can also use the strict ordering of elements as well with the help of the JSONValue.toJSONString(map) method i.e. by the implementation of java.util.LinkedHashMap.We can encode a JSON object in the below two examples.Example import java.util.*; import org.json.simple.JSONObject; public class JSONEncodingTest { public static void main(String[] args) { Map dataMap = new HashMap(); dataMap.put("Name", "Adithya"); dataMap.put("Age", new Integer(25)); dataMap.put("Salary", new Double(25000.00)); dataMap.put("Employee Id", new Integer(115)); dataMap.put("Company", "TutorialsPoint"); JSONObject ...
Read MoreHow can we convert a map to the JSON object in Java?
The JSON is a lightweight, text-based and language-independent data exchange format. The JSON can represent two structured types like objects and arrays. An object is an unordered collection of key/value pairs and an array is an ordered sequence of values. We can convert a Map to JSON object using the toJSONString() method(static) of org.json.simple.JSONValue. It has two important static methods: writeJSONString() method to encode an object into JSON text and write it out, escape() method to escape the special characters and escape quotes, \, /, \r, , \b, \f, \t.Exampleimport java.util.*; import org.json.simple.JSONValue; public class ConvertMapJSONTest { ...
Read MoreHow can we add a JSONArray to JSONObject in Java?
The JSON is a text-based format for exchanging data. It is a lightweight component and language independent. We can also add a JSONArray to JSONObject. We need to add a few items to an ArrayList first and pass this list to the put() method of JSONArray class and finally add this array to JSONObject using the put() method. Exampleimport org.json.*; import java.util.*; public class AddJSONArrayToJSONObjTest { public static void main(String args[]) { List list = new ArrayList(); list.add("Raja"); list.add("Jai"); ...
Read MoreHow can we write JSON objects to a file in Java?
The JSON is one of the widely used data-interchange formats and is a lightweight and language independent. The json.simple is a lightweight JSON processing library that can be used to write JSON files and it can be used to encode or decode JSON text and fully compliant with JSON specification(RFC4627). In order to read a JSON file, we need to download the json-simple.jar file and set the path to execute it.Exampleimport java.io.*; import java.util.*; import org.json.simple.*; import org.json.simple.parser.*; public class JSONObjectWriterToFileTest { public static void main(String[] args) throws IOException { JSONObject ...
Read MoreHow can we convert a JSON string to a JSON object in Java?
The JSON stands for JavaScript Object Notation and it can be used to transfer and storage of data. The JSONObject can parse text from a String to produce a map-like object. The object provides methods for manipulating its contents, and for producing a JSON compliant object serialization. The JSONArray can parse text from a String to produce a vector-like object. The object provides methods for manipulating its contents, and for producing a JSON compliant array serialization.In the below two examples, We can convert a JSON string to a JSON object.Example 1import org.json.JSONObject; import org.json.JSONArray; public class StringToJSONTest { ...
Read MoreHow to display a JFrame to the center of a screen in Java?
A JFrame is a subclass of Frame class and the components added to a frame are referred to as its contents, these are managed by the contentPane. We can add the components to a JFrame to use its contentPane instead. A JFrame is like a Window with border, title, and buttons. We can implement most of the java swing applications using JFrame.By default, a JFrame can be displayed at the top-left position of a screen. We can display the center position of JFrame using the setLocationRelativeTo() method of Window class.Syntaxpublic void setLocationRelativeTo(Component c)Exampleimport javax.swing.*; import java.awt.*; public class JFrameCenterPositionTest extends ...
Read MoreHow to display a JRadioButtonMenuItem in Java?
A JRadioButtonMenuItem is a subclass of the JMenuItem class in Java. A JRadioButtonMenuItem is a menu item that is part of a group of menu items in which only one item in the group can be selected and the selected item displays its selected state. We can add multiple radio button menu items to a ButtonGroup object to form a button group. If one radio button menu item in a button group is selected, all other radio button menu items will be unselected.Syntaxpublic class JRadioButtonMenuItem extends JMenuItem implements AccessibleExampleimport javax.swing.*; import java.awt.*; public class JRadioButtonMenuItemTest extends JFrame { private JMenuBar mb; ...
Read MoreWhen can we use the pack() method in Java?
The pack() method is defined in Window class in Java and it sizes the frame so that all its contents are at or above their preferred sizes. An alternative to the pack() method is to establish a frame size explicitly by calling the setSize() or setBounds() methods. In general, using the pack() method is preferable to call than setSize() method, since pack leaves the frame layout manager in charge of the frame size and layout managers are good at adjusting to platform dependencies and other factors that affect the component size.Syntaxpublic void pack()Exampleimport java.awt.*; import javax.swing.*; public class PackMethodTest extends JFrame { public ...
Read MoreHow can we apply different borders to JButton in Java?
A JButton is a subclass of AbstractButton class and it can be used for adding platform-independent buttons in a Java Swing application. A JButon can generate an ActionListener interface when the user clicking on a button, it can also generate MouseListener when a user can do some actions from the mouse and KeyListener when a user can do some actions from the keyboard.We can set different borders like LineBorder, BevelBorder, EtchcedBorder, EmptyBorder, TitledBorder, etc to JButton using the setBorder() method of JComponent class.Syntaxpublic void setBorder(Border border)Exampleimport javax.swing.*; import java.awt.*; public class JButtonBordersTest extends JFrame { private JButton ...
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