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JSON Articles
Page 13 of 16
How to ignore the multiple properties of a JSON object in Java?
The @JsonIgnoreProperties Jackson annotation can be used to specify a list of properties or fields of a class to ignore. The @JsonIgnoreProperties annotation can be placed above the class declaration instead of above the individual properties or fields to ignore.Syntax@Target(value={ANNOTATION_TYPE, TYPE, METHOD, CONSTRUCTOR, FIELD}) @Retention(value=RUNTIME) public @interface JsonIgnorePropertiesExampleimport java.io.*; import com.fasterxml.jackson.annotation.*; import com.fasterxml.jackson.databind.*; public class JsonIgnorePropertiesTest { public static void main(String[] args) throws IOException { Customer customer = new Customer("120", "Ravi", "Hyderabad"); System.out.println(customer); ObjectMapper mapper = new ObjectMapper(); String jsonString = mapper.writeValueAsString(customer); System.out.println("JSON: " + jsonString); ...
Read MoreWhen to use @JsonAutoDetect annotation in Java?
The @JsonAutoDetect annotation can be used at the class level to override the visibility of the properties of a class during serialization and deserialization. We can set the visibility with the properties like "creatorVisibility", "fieldVisibility", "getterVisibility", "setterVisibility" and "isGetterVisibility". The JsonAutoDetect class can define public static constants that are similar to Java class visibility levels like "ANY", "DEFAULT", "NON_PRIVATE", "NONE", "PROTECTED_AND_PRIVATE" and "PUBLIC_ONLY".Exampleimport com.fasterxml.jackson.annotation.*; import com.fasterxml.jackson.databind.*; import java.io.*; public class JsonAutoDetectTest { public static void main(String[] args) throws IOException { Address address = new Address("Madhapur", "Hyderabad", "Telangana"); Name name = new Name("Raja", "Ramesh"); Student student ...
Read MoreHow to serialize a JSON string to an Output Handler in Java?
The Flexjson is a lightweight library for serializing and deserializing Java objects into and from JSON format. A JSONSerializer is the main class for performing serialization of Java objects to JSON. We can serialize a JSON string to an Output Handler using the WriterOutputHandler class and it implements the OutputHandler interface.Syntaxpublic class WriterOutputHandler extends Object implements OutputHandlerExampleimport java.io.*; import flexjson.JSONSerializer; import flexjson.OutputHandler; import flexjson.WriterOutputHandler; public class JsonOutputHandlerTest { public static void main(String[] args) { JSONSerializer serializer = new JSONSerializer().prettyPrint(true); // pretty print JSON Employee emp = new Employee("Raja", "Ramesh", 28, "Hyderabad"); OutputHandler out = new WriterOutputHandler(new ...
Read MoreHow to auto-increment the property of a JSONObject in Java?
A JSONObject is an unordered collection of name/value pairs and parses text from a String to produce a map-like object. However, we can auto-increment the property of a JSONObject using the increment() method of JSONObject class. If there is no such property, create one with a value of 1. If there is such a property and if it is an Integer, Long, Double or Float then add one to it.Syntaxpublic JSONObject increment(java.lang.String key) throws JSONExceptionExampleimport org.json.JSONException; import org.json.JSONObject; public class IncrementJSONObjectTest { public static void main(String[] args) throws JSONException { JSONObject jsonObj = new JSONObject(); jsonObj.put("year", 2019); ...
Read MoreHow to wrap a JSON using flexjson in Java?
The Flexjson library is a lightweight Java library for serializing and de-serializing java beans, maps, arrays, and collections in a JSON format. A JSONSerializer is the main class for performing serialization of Java objects to JSON and by default performs a shallow serialization. We can wrap a JSON object using the rootName() method of JSONSerializer class, this method wraps the resulting JSON in a javascript object that contains a single field named rootName.Syntaxpublic JSONSerializer rootName(String rootName)Exampleimport flexjson.JSONSerializer; public class JSONRootNameTest { public static void main(String[] args) { JSONSerializer serializer = new JSONSerializer().rootName("My_Employee").prettyPrint(true); Employee emp = new Employee("Adithya", "Jai", 28, ...
Read MoreHow can we serialize a list of objects using flexjson in Java?
The Flexjson is a lightweight library for serializing and deserializing Java objects into and from JSON format. We can serialize a list of objects using the serialize() method of JSONSerializer class. This method can perform a shallow serialization of the target instance. We need to pass a list of objects of List type as an argument to the serialize() method.Syntaxpublic String serialize(Object target)Exampleimport flexjson.JSONSerializer; import java.util.*; public class JsonSerializeListTest { public static void main(String[] args) { JSONSerializer serializer = new JSONSerializer().prettyPrint(true); // pretty print JSON Student s1 = new Student("Raja", "Ramesh", 28, "Hyderabad"); Student s2 = new Student("Suresh", "Kumar", 30, "Chennai"); ...
Read MoreWhen can we call @JsonAnyGetter and @JsonAnySetter annotations in Java?\\n
The @JsonAnyGetter annotation enables to use a Map as a container for properties that we want to serialize to JSON and @JsonAnySetter annotation instructs Jackson to call the same setter method for all unrecognized fields in the JSON object, which means that all fields that are not already mapped to a property or setter method in the Java object.Syntaxpublic @interface JsonAnyGetter public @interface JsonAnyGetterExampleimport java.io.*; import java.util.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.*; import com.fasterxml.jackson.annotation.*; public class JsonAnyGetterAndJsonAnySetterTest { public static void main(String args[]) throws JsonGenerationException, JsonMappingException, IOException { Employee emp1 = new Employee(); emp1.setFirstName("Adithya"); emp1.setLastName("Sai"); ...
Read MoreConvert CSV to JSON using the Jackson library in Java?\\n
A Jackson is a Java JSON API that provides several different ways to work with JSON. We can convert CSV data to JSON data using the CsvMapper class, it is specialized ObjectMapper, with extended functionality to produce CsvSchema instances out of POJOs. We can use the reader() method for constructing ObjectReader with default settings. In order to convert this, we need to import the com.fasterxml.jackson.dataformat.csv package.In the below example, convert a CSV to JSON.Exampleimport java.io.*; import java.util.*; import com.fasterxml.jackson.databind.*; import com.fasterxml.jackson.dataformat.csv.*; public class CsvToJsonTest { public static void main(String args[]) throws Exception { File input = new File("input.csv"); try { ...
Read MoreHow to deserialize a JSON array to list generic type in Java?\\n
The Gson library provides a class called com.google.gson.reflect.TypeToken to store generic types by creating a Gson TypeToken class and pass the class type. Using this type, Gson can able to know the class passed in the generic class.Syntaxpublic class TypeToken extends ObjectWe can deserialize a JSON array to a generic type of list in the below exampleExampleimport java.lang.reflect.Type; import java.util.*; import com.google.gson.*; import com.google.gson.reflect.*; public class JSONArrayToListTest { public static void main(String args[]) throws Exception { String jsonStr = "[{\"name\":\"Adithya\", \"course\":\"Java\"}, " + "{\"name\":\"Ravi\", \"course\":\"Python\"}]"; Type listType = new TypeToken() {}.getType(); List students = ...
Read MoreHow 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\" : {\"3\" : {\"4\" : [5, { \"6\" : { \"7\" : 8 } } ] } ...
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