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Object Oriented Programming Articles
Page 432 of 589
How to convert JsonNode to ArrayNode using Jackson API in Java?
A JsonNode is a base class for all JSON nodes that forms the JSON Tree Model whereas ArrayNode is a node class that represents an array mapped from JSON content. We can convert or translate JsonNode to ArrayNode by typecasting the ArrayNode to retrieve the values using the readTree() method of ObjectMapper class and get() method for accessing the value of a specified element of an array node.Syntaxpublic JsonNode readTree(String content) throws IOException, com.fasterxml.jackson.core.JsonProcessingExceptionExampleimport com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.node.ArrayNode; import com.fasterxml.jackson.core.JsonProcessingException; public class JSonNodeToArrayNodeTest { public static void main(String args[]) throws JsonProcessingException { ...
Read MoreHow to search a value inside a JSON file using Jackson in Java?
The com.fasterxml.jackson.databind.node.ObjectNode class can be used to map the JSON object structure in Json content. We can search for a particular value inside the JSON file using the get() method of ObjectNode class, this method used for accessing the value of a specified field of an object node.Syntaxpublic JsonNode get(String fieldName)Exampleimport com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.node.ObjectNode; public class ObjectNodeTest { public static void main(String args[]) throws Exception { String jsonString = "{"Id":101, "name":"Raja Ramesh", "address":"Madhapur"}"; ObjectMapper mapper = new ObjectMapper(); ObjectNode ...
Read MoreHow to implement custom deserializer using @JsonDeserialize annotation in Java?
The @JsonDeserialize annotation is used to declare custom deserializer while deserializing JSON to Java object. We can implement a custom deserializer by extending the StdDeserializer class with a generic type Employee and need to override the deserialize() method of StdDeserializer class.Syntax@Target(value={ANNOTATION_TYPE, METHOD, FIELD, TYPE, PARAMETER}) @Retention(value=RUNTIME) public @interface JsonDeserializeIn the below program, we can implement a custom deserializer using @JsonDeserialize annotationExampleimport java.io.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.*; import com.fasterxml.jackson.databind.annotation.*; import com.fasterxml.jackson.databind.deser.std.*; public class JsonDeSerializeAnnotationTest { public static void main (String[] args) throws JsonProcessingException, IOException { Employee emp = new Employee(115, "Adithya"); ...
Read MoreHow to control serialization through @JSON annotation using flexjson in Java?
The @JSON annotation is used by JSONSerializer class to exclude or include a field during the serialization process. We can use the serialize() method of JSONSerializer class to perform a shallow serialization of the target instance.Syntax@Retention(value=RUNTIME) @Target(value={FIELD, TYPE, METHOD}) public @interface JSONExampleimport flexjson.JSONSerializer; import flexjson.JSON; public class JSONAnnotationTest { public static void main(String[] args) { JSONSerializer serializer = new JSONSerializer().prettyPrint(true); Employee emp = new Employee("Raja", "Ramesh", 30, "Hyderabad"); String jsonStr = serializer.serialize(emp); System.out.println(jsonStr); ...
Read MoreHow to implement custom serializer using @JsonSerialize annotation in Java?
The @JsonSerialize annotation is used to declare custom serializer during the serialization of a field. We can implement a custom serializer by extending the StdSeralizer class. and need to override the serialize() method of StdSerializer class.Syntax@Target(value={ANNOTATION_TYPE, METHOD, FIELD, TYPE, PARAMETER}) @Retention(value=RUNTIME) public @interface JsonSerializeIn the below program, we can implement a custom serializer using @JsonSerialize annotationExampleimport java.io.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.*; import com.fasterxml.jackson.databind.annotation.*; import com.fasterxml.jackson.databind.ser.std.*; public class JsonSerializeAnnotationTest { public static void main (String[] args) throws JsonProcessingException, IOException { Employee emp = new Employee(115, "Adithya", new String[] {"Java", "Python", "Scala"}); ...
Read MoreHow to convert a JSON string to a bean using JSON-lib API in Java?
The JSON-lib API is a java library to serialize and de-serialize java beans, maps, arrays, and collections in the JSON format. We need to convert a JSON string to a bean by converting a string to JSON object first then convert this to a java bean.Syntaxpublic static Object toBean(JSONObject jsonObject, Class beanClass)In the below program, we can convert a JSON string to a bean.Exampleimport net.sf.json.JSONObject; import net.sf.json.JSONSerializer; public class ConvertJSONStringToBeanTest { public static void main(String[] args) { String jsonStr = "{"firstName": "Adithya", "lastName": "Sai", "age": 30, "technology": "Java"}"; ...
Read MoreHow 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", ...
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