Manipulate Any Complex JSON with a Single JSONata Expression in Spring Boot

Introduction

In micro‑service architectures, heterogeneous JSON payloads are exchanged frequently. Hard‑coded conversion logic incurs high maintenance cost and long release cycles. JSONata4Java provides a declarative JSONata expression engine that can be configured at runtime, enabling dynamic data mapping without restarting services.

Adding the Dependency

<dependency>
  <groupId>com.ibm.jsonata4java</groupId>
  <artifactId>JSONata4Java</artifactId>
  <version>2.6.3</version>
</dependency>

The example assumes a Spring Boot 3.5.0 environment, which already includes Jackson; otherwise Jackson dependencies must be added.

Sample JSON Documents

{
  "FirstName": "王强",
  "Surname": "明辉",
  "Age": 28,
  "Address": {
    "Street": "科技园路88号",
    "City": "深圳市",
    "Postcode": "518057"
  },
  "Sno": [2,4,6,8,10],
  "Phone": [
    {"type":"home","number":"0755-8888 1234"},
    {"type":"office","number":"0755-6666 1234"},
    {"type":"office","number":"0755-6666 1235"},
    {"type":"mobile","number":"138 0000 1234"}
  ],
  "Email": [
    {"type":"work","address":["[email protected]","[email protected]"]},
    {"type":"home","address":["[email protected]","[email protected]"]}
  ],
  "Other": {
    "Over 18 ?": true,
    "Misc": null,
    "Alternative.Address": {
      "Street": "中山路168号",
      "City": "上海市",
      "Postcode": "200001"
    }
  }
}

{
  "Account": {
    "Order": [
      {
        "Product": [
          {"Product Name":"Bowler Hat","Price":34.45,"Quantity":2},
          {"Product Name":"Trilby hat","Price":21.67,"Quantity":1}
        ]
      },
      {
        "Product": [
          {"Product Name":"Bowler Hat","Price":34.45,"Quantity":4},
          {"Product Name":"Cloak","Price":107.99,"Quantity":1}
        ]
      }
    ]
  }
}

Basic Operations

Evaluating simple path expressions:

expression = "FirstName";
result = expressions.evaluate(jsonNode);
// Output: "王强"

expression = "Address.City";
// Output: "深圳市"

expression = "Phone[0]";
// Output: {"type":"home","number":"0755-8888 1234"}

expression = "Phone[0].number";
// Output: "0755-8888 1234"

expression = "Phone.number[0]";
// Output: ["0755-8888 1234","0755-6666 1234","0755-6666 1235","138 0000 1234"]

expression = "Phone[[0..1]]";
// Output: [{"type":"home","number":"0755-8888 1234"},{"type":"office","number":"0755-6666 1234"}]

Predicate Queries

Filtering with boolean predicates:

expression = "Phone[type='mobile']";
// Output: {"type":"mobile","number":"138 0000 1234"}

expression = "Phone[type='office'].number";
// Output: ["0755-6666 1234","0755-6666 1235"]

expression = "Address.*";
// Output: ["科技园路88号","深圳市","518057"]

expression = "*.Postcode";
// Output: "518057"

Functions & Expressions

String concatenation uses &. Numeric operators follow standard arithmetic.

expression = "FirstName & ' ' & Surname";
// Output: "王强 明辉"

expression = "Address.(Street & ', ' & City)";
// Output: "科技园路88号, 深圳市"

expression = "Sno[0] + Sno[1]";
// Output: 6

expression = "Sno[0] > Sno[1]";
// Output: FALSE

expression = "(Sno[2] != 4) and (Sno[3] != Sno[4])";
// Output: TRUE

Object Construction

expression = "Email.[address]";
// Output: [["[email protected]","[email protected]"],["[email protected]","[email protected]"]]

expression = "[Address, Other.`Alternative.Address`].City";
// Output: ["深圳市","上海市"]

expression = "Phone.{type: number}";
// Output: [{"home":"0755-8888 1234"},{"office":"0755-6666 1234"},{"office":"0755-6666 1235"},{"mobile":"138 0000 1234"}]

Grouping & Aggregation

expression = "Account.Order.Product{`Product Name`: Price}";
// Output: {"Bowler Hat":[34.45,34.45],"Trilby hat":21.67,"Cloak":107.99}

expression = """
        Account.Order.Product {
          `Product Name`: {"Price": Price, "Qty": Quantity}
        }
      """;
// Output: {"Bowler Hat":{"Price":[34.45,34.45],"Qty":[2,4]},"Trilby hat":{"Price":21.67,"Qty":1},"Cloak":{"Price":107.99,"Qty":1}}

expression = "Account.Order.Product{`Product Name`: $.(Price*Quantity)}";
// Output: {"Bowler Hat":[68.9,137.8],"Trilby hat":21.67,"Cloak":107.99}

expression = "$sum(Account.Order.Product.Price)";
// Output: 198.56

Array Functions

expression = "$count([1,2,3,1])";
// Output: 4

expression = "$append([1,2,3],[4,5,6])";
// Output: [1,2,3,4,5,6]

Sorting Example

expression = """
        $sort(Account.Order.Product, function($l, $r) {
          $l.Price * $l.Quantity > $r.Price * $r.Quantity
        })
      """;
// Result: [{"Product Name":"衬衣","Price":88,"Quantity":2},{"Product Name":"西裤","Price":230,"Quantity":1},{"Product Name":"内衣","Price":121,"Quantity":3}]

Reference

Complete list of JSONata functions and syntax: https://docs.jsonata.org/