How to search/find In JSON with java

Question

I have a below JSON string from the below i want to find/search criteria in JSON String.

1. To find the Number of keys present.
2. To get the values of given key(if we have array)

    {
    "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
    }

I am looking a solution like Groovy GPath Syntax

• store.book - size of this array.
• store.book[*].category - how may times the key present in the array.
• store.bicycle - if it found it has to return true value

Answer 1

You can also use the JsonPath project provided by REST Assured. This JsonPath project uses Groovy GPath expressions. In Maven you can depend on it like this:

<dependency>
    <groupId>com.jayway.restassured</groupId>
    <artifactId>json-path</artifactId>
    <version>2.4.0</version>
</dependency>

Examples:

To get a list of all book categories:

List<String> categories = JsonPath.from(json).get("store.book.category");

Get the first book category:

String category = JsonPath.from(json).get("store.book[0].category");

Get the last book category:

String category = JsonPath.from(json).get("store.book[-1].category");

Get all books with price between 5 and 15:

List<Map> books = JsonPath.from(json).get("store.book.findAll { book -> book.price >= 5 && book.price <= 15 }");

GPath is very powerful and you can make use of higher order functions and all Groovy data structures in your path expressions.