How to Get JSON response of AEM Page

Creating a Default servlet with a selector to get Page JSON Response
For the demo, I created a 'hcms' Selector to get Page JSON Response, when the request is made using 'hcms' selector the node would be converted into json and json response would be returned, it is like OOTB 'model' selector but with extension

Allow renaming properties
filter results(exclude properties based on config)
include reference response e.g. experience fragments

Uses
URL - http://host:port/resourcepath.hcms.json

Examples:
http://localhost:4504/content/we-retail/language-masters/en/men.hcms.json
http://localhost:4504/content/experience-fragments/demoxf/demoxf.hcms.json

with tidy selector
http://localhost:4504/content/experience-fragments/demoxf/demoxf.hcms.tidy.json

OSGi Config
exclude properties: list of properties to be excluded from json response
include references: list of properties which specify the reference of another resource.
rename properties: list of property to rename if response, e.g. originalname=newname
limit: to restrict lookup if there is infinite loop due to reference inclusion or the number of childnodes more then expected.


JSON Output
JSON output contains an array of node representation of json objects.
Each node object has the name, properties and childnodes items(properties).

The json object would not have properties or childnodes items if they are empty, That's means if the node doesn't contain any property(filtered) then there will be no properties item in json response and if there is no child node of a node then childnodes items will be not there in the response)

json representation of osgi configuration object :

{

  "name": "jcr:content",

  "properties": {

    "cq:tags": [],

    "jcr:title": "demoXF",

    "cq:xfVariantType": "web",

    "type": "weretail/components/structure/xfpage",

    "cq:template": "/conf/we-retail/settings/wcm/templates/experience-fragment-web-variation",

    "cq:xfMasterVariation": true

  },

  "childnodes": [

    {

      "name": "root",

      "properties": {

        "type": "wcm/foundation/components/responsivegrid"

      },

      "childnodes": [

        {

          "name": "product_grid",

          "properties": {

            "tagsMatch": "any",

            "pages": [

              "/content/we-retail/language-masters/en/products/men/shirts/eton-short-sleeve-shirt",

              "/content/we-retail/language-masters/en/products/men/pants/trail-model-pants",

              "/content/we-retail/language-masters/en/products/men/shorts/pipeline-board-shorts",

              "/content/we-retail/language-masters/en/products/men/shirts/amsterdam-short-sleeve-travel-shirt",

              "/content/we-retail/language-masters/en/products/men/shorts/buffalo-plaid-shorts",

              "/content/we-retail/language-masters/en/products/men/coats/portland-hooded-jacket"

            ],

            "feedEnabled": true,

            "displayAs": "products",

            "listFrom": "static",

            "limit": "6",

            "orderBy": "jcr:title",

            "type": "weretail/components/content/productgrid",

            "pageMax": "0"

          }

        },

        {

          "name": "image",

          "properties": {

            "isDecorative": "false",

            "altValueFromDAM": "true",

            "titleValueFromDAM": "true",

            "fileReference": "/content/dam/core-components-examples/library/sample-assets/mini.jpg",

            "displayPopupTitle": "true",

            "type": "weretail/components/content/image"

          }

        }

      ]

    }

  ]

} 

POM Gson dependency
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.5</version>
</dependency>