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JSON Articles
Page 12 of 16
How to handle the errors generated while deserializing a JSON in Java?
The DeserializationProblemHandler class can be registered to get called when a potentially recoverable problem is encountered during the deserialization process. We can handle the errors generated while deserializing the JSON by implementing the handleUnknownProperty() method of DeserializationProblemHandler class.Syntaxpublic boolean handleUnknownProperty(DeserializationContext ctxt, JsonParser p, JsonDeserializer deserializer, Object beanOrClass, String propertyName) throws IOExceptionExampleimport java.io.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.*; import com.fasterxml.jackson.databind.deser.*; public class DeserializationErrorTest { public static void main(String[] args) throws JsonMappingException, JsonGenerationException, IOException { String jsonString = "{"id":"101", "name":"Ravi Chandra", "address":"Pune", "salary":"40000" }"; ObjectMapper objectMapper = new ...
Read MoreHow to merge two JSON strings in an order using JsonParserSequence in Java?
The JsonParserSequence is a helper class that can be used to create a parser containing two sub-parsers placed in a particular sequence. We can create a sequence using the static method createFlattened() of the JsonParserSequence class.Syntaxpublic static JsonParserSequence createFlattened(JsonParser first, JsonParser second)Exampleimport java.io.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.core.util.*; public class JsonParserSequenceTest { public static void main(String[] args) throws JsonParseException, IOException { String jsonString1 = "{"id":"101", "name":"Ravi Chandra", "address":"Pune"}"; String jsonString2 = "{"id":"102", "name":"Raja Ramesh", "address":"Hyderabad", "contacts":[{"mobile":"9959984805", "home":"7702144400"}]}"; JsonFactory jsonFactory = ...
Read MoreHow to map the JSON data with Jackson Object Model in Java?
The ObjectMapper class provides functionality for converting between Java objects and matching JSON constructs. We can achieve mapping of JSON data represented by an Object Model to a particular Java object using a tree-like data structure that reads and stores the entire JSON content in memory. In the first step, read the JSON data into the JsonNode object then mapped it to another instance by calling the treeToValue() method of ObjectMapper class.Syntaxpublic T treeToValue(TreeNode n, Class valueType) throws JsonProcessingExceptionExampleimport java.io.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.*; public class JsonTreeModelDemo { public static void main(String[] args) throws JsonProcessingException, IOException ...
Read MoreHow to implement custom FieldNamingStrategy using Gson in Java?
The FieldNamingStrategy is a mechanism for providing custom field naming in Gson. This allows the client code to translate field names into a particular convention that is not supported as a normal Java field declaration rules. The translateName() method will prefix every field name with the string “pre_”.In the below example, we can implement the Custom FieldNamingStrategy.Exampleimport java.lang.reflect.Field; import com.google.gson.*; public class GsonFieldNamingStrategyTest { public static void main(String[] args) { Employee emp = new Employee(); emp.setEmpId(115); emp.setFirstName("Adithya"); ...
Read MoreHow to get the JsonFactory settings using Jackson in Java?
The JsonFactory class is a thread-safe and responsible for creating instances of writer and reader. The list of settings that can be turned on/off is present in an enumeration JsonFactory.Feature, it contains static method values() that return the enum constant of this type with the specified name.Syntaxpublic static enum JsonFactory.Feature extends EnumExampleimport com.fasterxml.jackson.core.JsonFactory; public class JsonFactorySettingsTest { public static void main(String[] args) { JsonFactory jsonFactory = new JsonFactory(); for(JsonFactory.Feature feature : JsonFactory.Feature.values()) { boolean result = ...
Read MoreFieldNamingPolicy enum using Gson in Java?
Gson library provides the naming conventions as part of enum FieldNamingPolicy. We can set the field naming policy using the setFieldNamingPolicy() method of the GsonBuilder class.FieldNamingPolicy enum ConstantsIDENTITY − Using this naming policy, the field name is unchanged.LOWER_CASE_WITH_DASHES − Using this naming policy, modify the Java Field name from its camel-cased form to a lower case field name where each word is separated by a dash (-).LOWER_CASE_WITH_UNDERSCORES − Using this naming policy, modify the Java Field name from its camel-cased form to a lower case field name where each word is separated by an underscore (_).UPPER_CAMEL_CASE − Using this naming ...
Read MoreHow to get the values of a key using the JsonPointer interface in Java?
The JSONPointer is a standard that defines a string syntax that can be used to access a particular key value in the JSON document. An instance of JSONPointer can be created by calling the static factory method createPointer() on the Json class. In the JSONPointer, every string syntax is prefixed with “/”. We can get the value of a key by calling the getValue() method on the JsonPointer object.JSON fileExampleimport javax.json.*; import java.io.*; public class JsonPointerTest { public static void main(String[] args) throws Exception { JsonReader jsonReader = Json.createReader(new FileReader("simple.json")); ...
Read MoreImportance of the JsonPatch interface in Java?
The JsonPatch interface is a format for storing a sequence of operations that can be applied to the target JSON structure. There are few operations like add, remove, replace, copy, move and test can be stored in JsonPath and operated on JSON structure. The JsonPatchBuilder interface can be used for constructing a JSON patch using the Json.createPatchBuilder().JSON fileExampleimport java.io.*; import javax.json.Json; import javax.json.JsonPatch; import javax.json.JsonPatchBuilder; import javax.json.JsonReader; import javax.json.JsonStructure; public class JsonPatchTest { public static void main(String[] args) throws Exception { JsonPatchBuilder jsonPatchBuilder = Json.createPatchBuilder(); JsonPatch jsonPatch = jsonPatchBuilder.add("/postalCode", "500072").remove("/age").build(); JsonReader reader = Json.createReader(new FileReader("simple.json")); ...
Read MoreHow to create a JSON using JsonObjectBuilder and JsonArrayBuilder in Java?
The JsonObjectBuilder can be used for creating JsonObject models whereas the JsonArrayBuilder can be used for creating JsonArray models. The JsonObjectBuilder can be created using the Json class, it contains methods to create the builder object and build an empty JsonObject instance using the Json.createObjectBuilder().build(). The JsonArrayBuilder can be created using the Json class, it contains methods to create the builder object and build an empty JsonArray instance using Json.createArrayBuilder().build().Exampleimport java.io.*; import javax.json.*; public class JsonObjectTest { public static void main(String[] args) { JsonObject empObject = Json.createObjectBuilder().add("empName", "Jai") ...
Read MoreHow to parse a JSON string using Streaming API in Java?
The Streaming API consists of an important interface JsonParser and this interface contains methods to parse JSON in a streaming way and provides forward, read-only access to JSON data. The Json class contains the methods to create parsers from input sources. We can parse a JSON using the static method createParser() of Json class.Syntaxpublic static JsonParser createParser(Reader reader)Exampleimport java.io.*; import javax.json.Json; import javax.json.stream.JsonParser; import javax.json.stream.JsonParser.Event; public class JSONParseringTest { public static void main(String[] args) { String jsonString = "{"name":"Adithya", "employeeId":"115", "age":"30"}"; JsonParser parser = ...
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