com.mgnt.utils

Class JsonUtils

java.lang.Object

com.mgnt.utils.JsonUtils

public class JsonUtils
extends java.lang.Object

This class provides basic JSON parsing (serialization/deserialization) functionality. It allows any class serialization (or List/Set/Map that contains any class) into a valid JSON string and to deserialize any JSON String back into any class. However, it doesn't work well with deserializing List/Set/Map that contains some classes and not just primitives. Note that this class uses JSON-JACKSON library and is making some operations simpler. However, the price for simplicity is that it can not handle properly deserialization of data structures. For that you will need to to work directly with JSON-JACKSON library (or any other JSON library). Or as an alternative you can deserialize it into a Map<String, Object> or List<Object> and than deserialize each Object separately.

Author:

Michael Gantman

Constructor Summary

Constructors

Constructor and Description
JsonUtils()

Method Summary

Modifier and Type	Method and Description
static <T> T	readObjectFromJsonString(java.lang.String jsonString, java.lang.Class<T> type) This is a helper method that invokes readObjectFromJsonString(String, Class, boolean) with the second parameter set to false.
static <T> T	readObjectFromJsonString(java.lang.String jsonString, java.lang.Class<T> type, boolean enableDefaultTyping) This method reads (deserializes) JSON string into specific Object type with option to allow or disallow default typing.
static java.lang.String	writeObjectToJsonString(java.lang.Object object) This is a helper method that invokes writeObjectToJsonString(Object, boolean) with the second parameter set to false.
static java.lang.String	writeObjectToJsonString(java.lang.Object object, boolean enableDefaultTyping) This method writes (serializes) an Object into JSON String with option to allow or disallow default typing.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JsonUtils

public JsonUtils()

Method Detail

writeObjectToJsonString

public static java.lang.String writeObjectToJsonString(java.lang.Object object,
                                                       boolean enableDefaultTyping)
                                                throws com.fasterxml.jackson.core.JsonProcessingException

This method writes (serializes) an Object into JSON String with option to allow or disallow default typing. If Default typing is enabled then the type validator used is class com.fasterxml.jackson.databind.jsontype.DefaultBaseTypeLimitingValidator. If you are not familiar with default typing concept in JASON-JACKSON library than simply use helper method writeObjectToJsonString(Object). It will do the job in most cases

Parameters:

object - an Object to be deserialized

enableDefaultTyping - boolean flag that determines if default typing is allowed

Returns:

valid JSON string that is the result of the Object deserialization

Throws:

com.fasterxml.jackson.core.JsonProcessingException

See Also:

writeObjectToJsonString(Object)

writeObjectToJsonString

public static java.lang.String writeObjectToJsonString(java.lang.Object object)
                                                throws com.fasterxml.jackson.core.JsonProcessingException

This is a helper method that invokes writeObjectToJsonString(Object, boolean) with the second parameter set to false. In most cases (when you don't need to worry about default typing) this method should be used instead of invoking method writeObjectToJsonString(Object, boolean)

Parameters:

object - an Object to be deserialized

Returns:

valid JSON string that is the result of the Object deserialization

Throws:

com.fasterxml.jackson.core.JsonProcessingException

readObjectFromJsonString

public static <T> T readObjectFromJsonString(java.lang.String jsonString,
                                             java.lang.Class<T> type,
                                             boolean enableDefaultTyping)
                                      throws java.io.IOException

This method reads (deserializes) JSON string into specific Object type with option to allow or disallow default typing. If Default typing is enabled then the type validator used is class com.fasterxml.jackson.databind.jsontype.DefaultBaseTypeLimitingValidator. If you are not familiar with default typing concept in JASON-JACKSON library than simply use helper method readObjectFromJsonString(String, Class). It will do the job in most cases

Just a short example: Assume that there is a class Person and an instance of this class was serialized to JSON String. And now there is a need to deserialize it back. So the code to do so would look like this:

Person person = JSONUtils.readObjectFromJsonString(jsonString, Person.class, false);

Type Parameters:

T - A class instance of which will be returned if deserialization succeeds.

Parameters:

jsonString - JSON string to be deserialized

type - deserialization target class

enableDefaultTyping - boolean flag that determines if default typing is allowed

Returns:

instance of class T deserialized from JSON string

Throws:

java.io.IOException

See Also:

readObjectFromJsonString(String, Class)

readObjectFromJsonString

public static <T> T readObjectFromJsonString(java.lang.String jsonString,
                                             java.lang.Class<T> type)
                                      throws java.io.IOException

This is a helper method that invokes readObjectFromJsonString(String, Class, boolean) with the second parameter set to false. In most cases (when you don't need to worry about default typing) this method should be used instead of invoking method readObjectFromJsonString(String, Class, boolean)

Just a short example: Assume that there is a class Person and an instance of this class was serialized to JSON String. And now there is a need to deserialize it back. So the code to do so would look like this:

Person person = JSONUtils.readObjectFromJsonString(jsonString, Person.class);

Type Parameters:

T - A class instance of which will be returned if deserialization succeeds.

Parameters:

jsonString - JSON string to be deserialized

type - deserialization target class

Returns:

instance of class T deserialized from JSON string

Throws:

java.io.IOException