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Articles by raja
Page 15 of 38
How can we use @Since annotation using Gson in Java?
The @Since annotation can use with the setVersion() method of the GsonBuilder class. This annotation can apply to a field in java class and accepts float as an argument. This argument represents the version number in which the field has serialized. The same can apply to the deserialization process.Syntax@Documented @Retention(value=RUNTIME) @Target(value={FIELD, TYPE}) public @interface SinceExampleimport com.google.gson.annotations.Since; import com.google.gson.Gson; import com.google.gson.GsonBuilder; public class GsonSinceAnnotationTest { public static void main(String[] args) { Employee emp = new Employee(); emp.setEmployeeName("Raja Ramesh"); emp.setEmployeeId(125); ...
Read MoreHow to convert a bean to XML without type hints using JSON-lib API in Java?
The JSON-lib is a Java library for serializing and de-serializing java beans, maps, arrays, and collections in JSON format. We can convert a bean to XML without type hints using the setTypeHintsEnabled() method of XMLSerializer class, this method sets whether JSON types can be included as attributes. We can pass false as an argument to this method to disable the type hints in XML.Syntaxpublic void setTypeHintsEnabled(boolean typeHintsEnabled)Exampleimport net.sf.json.JSONObject; import net.sf.json.xml.XMLSerializer; public class ConvertBeanToXMLNoHintsTest { public static void main(String[] args) { Employee emp = new Employee("Krishna Vamsi", 115, 30, "Java"); ...
Read MoreHow to convert a bean to XML using JSON-lib API in Java?
The net.sf.json.xml.XMLSerializer class is a utility class for transforming JSON to XML. When transforming JSONObject instance to XML, this class can add hints for converting back to JSON. We can use the write() method of XMLSerializer class to write a JSON value into an XML string with UTF-8 encoding and it can return a string representation of a well-formed XML document.Syntaxpublic String write(JSON json)Exampleimport net.sf.json.JSONObject; import net.sf.json.xml.XMLSerializer; public class ConvertBeanToXMLTest { public static void main(String[] args) { Student student = new Student("Sai", "Adithya", 25, "Pune"); ...
Read MoreHow to convert bean to JSON object by excluding some properties using JsonConfig in Java?
The JsonConfig class is a utility class that helps to configure the serialization process. We can convert a bean to a JSON object with few properties that can be excluded using the setExcludes() method of JsonConfig class and pass this JSON config instance to an argument of static method fromObject() of JSONObject.Syntaxpublic void setExcludes(String[] excludes)In the below example, we can convert bean to a JSON object by excluding some of the properties.Exampleimport net.sf.json.JSONObject; import net.sf.json.JsonConfig; public class BeanToJsonExcludeTest { public static void main(String[] args) { Student student = new Student("Raja", "Ramesh", ...
Read MoreHow to add elements to JSON Object using JSON-lib API in Java?
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 ...
Read MoreHow to serialize and deserialize a JSON using the ExclusionStrategy interface in Java?
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(); ...
Read MoreHow can we update an existing JSON data using javax.json API in Java?
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 { ...
Read MoreJSON Schema Support using Jackson in Java?
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 ...
Read MoreHow to convert Java array or ArrayList to JsonArray using Gson in Java?
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", ...
Read MoreHow to resolve "Expected BEGIN_OBJECT but was BEGIN_ARRAY" using Gson in Java?
While deserializing, a Gson can expect a JSON object but it can find a JSON array. Since it can't convert from one to the other, it can throw an error as "JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY" at the runtime.Exampleimport com.google.gson.Gson; public class GsonErrorTest { public static void main(String args[]) throws Exception { String json = "{"employee":[{"name":"Raja Ramesh", "technology":"java"}]}"; Gson gson = new Gson(); Software software = gson.fromJson(json, Software.class); System.out.println(software); ...
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