Raja has Published 432 Answers

How to convert a JSON object to an enum using Jackson in Java?

raja
raja
Published on 18-Oct-2019 17:51:24
A JSONObject can parse the text from String to produce a Map kind of an object. An Enum can be used to define a collection of constants, when we need a predefined list of values which do not represent some kind of numeric or textual data then we can use an enum. We ... Read More

Importance of the Jackson @JsonInclude annotation in Java?

raja
raja
Published on 18-Oct-2019 15:58:07
The Jackson @JsonInclude annotation can be used to exclude the properties or fields of a class under certain conditions and it can be defined using the JsonInclude.Include enum. The JsonInclude.Include enum contains few constants like "ALWAYS", "NON_DEFAULT", "NON_EMPTY" and "NON_NULL" to determine whether to exclude the property(field) or not.Syntaxpublic static enum JsonInclude.Include extends Enum<JSonInclude.Include>Exampleimport com.fasterxml.jackson.annotation.*; ... Read More

How can we sort a JSONObject in Java?

raja
raja
Published on 18-Oct-2019 14:08:54
A JSONObject is an unordered collection of a key, value pairs, and the values can be any of these types like Boolean, JSONArray, JSONObject, Number and String. The constructor of a JSONObject can be used to convert an external form JSON text into an internal form whose values can be retrieved with ... Read More

What is the use of @JacksonInject annotation using Jackson in Java?

raja
raja
Published on 18-Oct-2019 11:07:31
The Jackson @JacksonInject annotation can be used to inject the values into parsed objects instead of reading those values from the JSON. In order to inject values into a field, we can use the InjectableValues class and need to configure the ObjectMapper class to read both the injected values from the ... Read More

How to ignore a class during the serialization using Jackson in Java?

raja
raja
Published on 17-Oct-2019 16:33:44
The Jackson @JsonIgnoreType annotation can be used to ignore a class during the serialization process and it can mark all the properties or fields of a class to be ignored while serializing and deserializing a JSON object.Syntax@Target(value={ANNOTATION_TYPE, TYPE}) @Retention(value=RUNTIME) public @interface JsonIgnoreTypeExampleimport com.fasterxml.jackson.annotation.*; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.*; import java.io.*; public class JsonIgnoreTypeTest {    public static ... Read More

How to add a JSON string to an existing JSON file in Java?

raja
raja
Published on 17-Oct-2019 14:19:36
A Gson is a json library for Java and it can be used to generate a JSON. In the initial step, we can read a JSON file and parsing to a Java object then need to typecast the Java object to a JSonObject and parsing to a JsonArray. Then iterating this JSON array ... Read More

When to use @JsonAutoDetect annotation in Java?

raja
raja
Published on 17-Oct-2019 11:14:10
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 ... Read More

How to rename the properties of JSON using Gson in Java?

raja
raja
Published on 16-Oct-2019 17:31:48
The Gson @SerializedName annotation can be serialized to a JSON with the provided name value as its field name. This annotation can override any FieldNamingPolicy including the default field naming policy that may have been set on the Gson instance. A different naming policy can set using the GsonBuilder class.Syntax@Retention(value=RUNTIME) ... Read More

How to ignore the multiple properties of a JSON object in Java?

raja
raja
Published on 16-Oct-2019 15:58:17
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 ... Read More

How to serialize a JSON string to an Output Handler in Java?

raja
raja
Published on 16-Oct-2019 14:41:29
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 ... Read More
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