🧪Extracting Values from Local JSON Using JsonPath in Rest Assured

Author: Dinesh Y S

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🔍Introduction

When working with API responses, validating JSON data is a common task. But what if you want to practice or test your logic using a local JSON file instead of hitting a live API?

In this post, I’ll show you how to:

• Read a local JSON file in Java

• Use JsonPath to extract values

• Filter JSON arrays using Groovy-style expressions like find and it

📁Sample JSON File

Save this as users.json in your src/test/resources/testData/ folder:

[
{ "id": 1, "firstName": "John", "status": "active" },
{ "id": 2, "firstName": "John", "status": "inactive" },
{ "id": 3, "firstName": "Dinesh", "status": "pending" }
]

🛠️Utility to Read JSON File

import java.nio.file.Files;
import java.nio.file.Paths;

public class JsonUtils {
/**
 * Reads a JSON from the given file path and returns it as a String 
 * @param filePath path to the JSON file
 * @return JSON content as String
 * @throws Exception if file reading fails
 */
public static String readJson(String filePath) throws Exception{
    return new String(Files.readAllBytes(Paths.get(filePath)));
}
}

🧪Test Class Using JsonPath

import io.restassured.path.json.JsonPath;
import org.testng.Assert;
import org.testng.annotations.Test;

public class LocalJsonTest {

@Test
public void testGetStatusByIdAndfirstName() throws Exception {
      String json = JsonUtil.readJson("src/test/resources/testData/users.json");

      JsonPath jsonPath = new JsonPath(json);
      // Extract sttaus using Groovy-style filter
      String status = jsonPath.getString("find{ it.id == 3 &7 it.firstname == 'Dinesh' }.status");
      Assert.assertEquals(status, "pending", "Status should match for given ID and firstName");
}
}

🧠Why find and it?

• find {} is a Groovy method that returns the first matching element

• it refers to the current object in the iteration.

So this line:

jsonPath.getString("find { it.id == 3 && it.firstName == 'Dinesh' }.status");

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….means: “ Find the first object where id is 3 and firstName is Dinesh, and returns its status.”

✅Conclusion

This is great way to practice JSONPath filtering without relying on external APIs. You can extend this by:

• Using findAll to get multiple matches

• Adding DataProvider for parameterized tests

• Validating nested JSON structures