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https://github.com/arakelian/jackson-utils

Useful utilities when using Jackson for JSON serialization and deserialization
https://github.com/arakelian/jackson-utils

helper jackson java java-11 java-8 json serialization utility utility-library zoneddatetime

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Useful utilities when using Jackson for JSON serialization and deserialization

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# jackson-utils

[![version](https://img.shields.io/maven-metadata/v.svg?label=release&metadataUrl=https://repo1.maven.org/maven2/com/arakelian/jackson-utils/maven-metadata.xml)](https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.arakelian%22%20AND%20a%3A%22jackson-utils%22)

[![CI](https://github.com/arakelian/jackson-utils/actions/workflows/ci.yml/badge.svg)](https://github.com/arakelian/jackson-utils/actions/workflows/ci.yml)



Utilities for reading and writing JSON and XML using Jackson.



## Requirements



* Versions < 4.0.0 require Java 8+

* Version 4+ require Java 11+



## Serialization and Deserialization



### Enumerated Types



When deserializating strings into Java `Enum` types, it's useful to be able to accept lowercase, uppercase and mixed-cased string input.



This deserializer attempts to coerce the string value using the provided case first, but then falls back to UPPERCASE or lowercase if needed.



```java

objectMapper.registerModule(new SimpleModule()

        .setDeserializerModifier(new EnumUppercaseDeserializerModifier()));

```



### Trimming Whitespace



When deserializing string values, it's useful to automatically trim leading and trailing whitespace including newlines, tabs, etc.



This deserializer uses the `Character.isWhitespace(char)` function to determine what is whitespace.



```java

objectMapper.registerModule(new SimpleModule()

        .addDeserializer(String.class, TrimWhitespaceDeserializer.SINGLETON));

```



### ZonedDateTime



When serializing and deserializing ZonedDateTime values, it's useful to accept a wide variety of string formats.



In addition to the widely-supported ISO date format, you also get variety of other common formats:

* yyyy-MM-dd

* yyyyMMdd

* yyyyMMMddd

* MM/dd/yyyy

* MM-dd-yyyy

* MM.dd.yyyy

* dd-MMM-yyyy

* MMM dd, YYYY

* MMMM dd, yyyy



```java

objectMapper.registerModule(new SimpleModule()

        .addSerializer(new ZonedDateTimeSerializer()) //

        .addDeserializer(ZonedDateTime.class, new ZonedDateTimeDeserializer());

```



### GeoPoint



This library exposes an immutable `GeoPoint` class that represents a lat/lon coordinate.  `GeoPoint` supports a

variety of serialization and deserialization options, which happen to be compatible with those used by

[Elasticsearch](https://www.elastic.co/guide/en/elasticsearch/reference/current/geo-point.html).



#### Latitude and longitude fields



```json

"location": {

  "lat": 41.12,

  "lon": -71.34

}

```



#### Comma separated latitude and longitude



```json

"location": "41.12,-71.34"

```



#### Geohash



```json

"location": "drm3btev3e86"

```



## MapPath



When deserializing JSON that does not conform to a fixed schema, it's sometimes useful to deserialize the JSON to native Java objects like `Map` and `List`

instead using Jackson's tree structure (e.g. `JsonNode`).



When we do this however we lose the ability to traverse the data in an easy way and null-safe manner. Enter `MapPath`, which is loosely 

inspired by [JsonPath](https://github.com/json-path/JsonPath).



Let's assume the following JSON input:



```java

{

  "store": {

    "book": [

      {

        "category": "reference",

        "author": "Nigel Rees",

        "title": "Sayings of the Century",

        "price": 8.95

      },

      {

        "category": "fiction",

        "author": "Evelyn Waugh",

        "title": "Sword of Honour",

        "price": 12.99

      },

      {

        "category": "fiction",

        "author": "Herman Melville",

        "title": "Moby Dick",

        "isbn": "0-553-21311-3",

        "price": 8.99

      },

      {

        "category": "fiction",

        "author": "J. R. R. Tolkien",

        "title": "The Lord of the Rings",

        "isbn": "0-395-19395-8",

        "price": 22.99

      }

    ],

    "bicycle": {

      "color": "red",

      "price": 19.95

    }

  },

  "expensive": 10

}

```



Let's use Jackson to parse this JSON into a Map.



```java

String json = "...see above...";

Map map = objectMapper.readValue(json, Map.class);

```



Let's wrap the Map using `MapPath`



```java

MapPath mapPath = MapPath.of(map);

```



Now we can traverse the properties of the map very easily:



```java

   mapPath.getString("store.bicycle.color")    ' red

   mapPath.getDouble("store.bicycle.price")    ' 19.95

   mapPath.getInt("expensive")                 ' 10

```



## Installation



The library is available on [Maven Central](https://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22com.arakelian%22%20AND%20a%3A%22jackson-utils%22).



### Maven



Add the following to your `pom.xml`:



```xml



    

        central

        Central Repository

        http://repo.maven.apache.org/maven2

        

            true

        

    



...



    com.arakelian

    jackson-utils

    4.0.1

    compile



```



### Gradle



Add the following to your `build.gradle`:



```groovy

repositories {

  mavenCentral()

}



dependencies {

  compile 'com.arakelian:jackson-utils:4.0.1'

}

```



## Licence



Apache Version 2.0