Source link: https://github.com/Instagram/ig-json-parser

ig-json-parser

Fast JSON parser for java projects.

Getting started

The easiest way to get started is to look at maven-example. For more comprehensive examples, check out the unit tests or the demo.

Gradle

For Java projects, to use this library, add this to your build.gradle file:

allprojects {

repositories {

  maven {
 url 'https://jitpack.io' 
}

}
 
}
  ...  dependencies {

compile 'com.github.instagram.ig-json-parser:runtime:master-SNAPSHOT' // the runtime
compile 'com.github.instagram.ig-json-parser:processor:master-SNAPSHOT' // the annotation processor  
}

For Android projects using Android Studio 3.0+ or Gradle 4.0+, you can enable the annotation processor as following:

allprojects {

repositories {

  maven {
 url 'https://jitpack.io' 
}

}
 
}
  ...  dependencies {

annotationProcessor 'com.github.instagram.ig-json-parser:processor:master-SNAPSHOT'
implementation 'com.github.instagram.ig-json-parser:runtime:master-SNAPSHOT' 
}

If you are using older gradle versions, you can use old apt plugin to integrate the annotation processor:

allprojects {

repositories {

  maven {
 url 'https://jitpack.io' 
}

}
 
}
  ...  apply plugin: 'com.neenbedankt.android-apt'  dependencies {

apt 'com.github.instagram.ig-json-parser:processor:master-SNAPSHOT'
compile 'com.github.instagram.ig-json-parser:runtime:master-SNAPSHOT' 
}

If you are using other build sytems, please find instructions here

Requirements for model classes

There should be a package-visible no-argument constructor for each of your model classes. The fields also need to be package-visible.

Each class that needs a serializer/deserializer generated should be annotated with @JsonType. Each field that needs to be mapped to/from JSON should be annotated with @JsonField. The @JsonField annotation has one mandatory argument, which is the fieldname for the field in the JSON.

The following is an example of a very simple model class:

@JsonType class Dessert {

@JsonField(fieldName="type")
String type;
 @JsonField(fieldName="rating")
float rating; 
}

Serializer/deserializer

Compiling your model classes with the annotations will automatically generate the serializer and deserializer. They will be in a generated class with the same name as your class, except with the suffix __JsonHelper. For example, to deserialize the Dessert class above, simply run the code:

Dessert parsed = Dessert__JsonHelper.parseFromJson(inputJsonString);

To serialize a class, run:

String serialized = Dessert__JsonHelper.serializeToJson(dessertObject);

Supported data types

The following scalar types are supported:

String
boolean/Boolean
int/Integer
long/Long
float/Float
double/Double

If a json field is another dictionary, it can be represented by another model class. That model class must also have the @JsonType annotation.

Lists of objects are supported either as Java Lists or Queues.

Proguard

Add the following lines to your proguard-rules file:

-dontwarn sun.misc.Unsafe -dontwarn javax.annotation.**

Advanced features

Postprocessing

TODO: Document this. See the documentation in common/src/main/java/com/instagram/common/json/annotation/JsonType.java in the meanwhile.

Customized parsing code

TODO: Document this. See the documentation in common/src/main/java/com/instagram/common/json/annotation/JsonField.java in the meanwhile.

Optional serializer generation

To save generating serializer code if you only need deserialization, serializer generation can be disabled or enabled globally and per-class. The default is to generate serializers for all classes. To disable generation globally, pass