As a part of the End to End REST Assured Tutorial, in this post, we will learn to compare two JSON using the Jackson library.
We may need to compare two JSON during API testing. For example – If we are going to get the same JSON response for an API every time or some parts of the response are always constant then instead of writing some logic to assert them, we can directly compare with an existing JSON response.
We have a couple of good Java libraries to do. In this post, we will use Jackson Library to compare two JSON responses.
com.fasterxml.jackson.core jackson-databind 2.12.1
An abstract class JsonNode provided by Jackson API provides an abstract method called equals() which can be used to compare node objects. Equality for node objects is defined as a full (deep) value equality. This means that it is possible to compare complete JSON trees for equality by comparing the equality of root nodes. equals() method is an abstract method and implemented by ObjectNode and ArrayNode classes.
We need to convert the given JSON to JsonNode ( or ObjectNode or ArrayNode) first and then we can call the equals method on it.
- The above method will return true if JSON nodes are equal.
- The order of root elements in JSON nodes will not matter.
- The order of elements in the JSON array will matter and it will not be the same.
package CompareJSONUsingJackson;
import org.testng.annotations.Test;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
public class CompareJsonObjects {
String JsonObject1;
String jsonObject2;
ObjectMapper objectMapper;
JsonNode jsonNode1;
JsonNode jsonNode2;
@Test
public void compareTwoJsonObjects() throws JsonMappingException, JsonProcessingException
{
JsonObject1 = "{\r\n" +
" \"firstName\" : \"Amod\",\r\n" +
" \"lastName\" : \"Mahajan\"\r\n" +
"}";
jsonObject2 = "{\r\n" +
" \"firstName\" : \"Amod\",\r\n" +
" \"lastName\" : \"Mahajan\"\r\n" +
"}";
objectMapper = new ObjectMapper();
jsonNode1 = objectMapper.readTree(JsonObject1);
jsonNode2 = objectMapper.readTree(jsonObject2);
// Checking if both json objects are same
System.out.println(jsonNode1.equals(jsonNode2));
}
@Test
public void compareTwoJsonObjectsWithDifferentOrderOfRootElements() throws JsonMappingException, JsonProcessingException
{
// Change in order of elements does not impact
JsonObject1 = "{\r\n" +
" \"firstName\" : \"Amod\",\r\n" +
" \"lastName\" : \"Mahajan\"\r\n" +
"}";
jsonObject2 = "{\r\n" +
" \"lastName\" : \"Mahajan\",\r\n" +
" \"firstName\" : \"Amod\"\r\n" +
" \r\n" +
"}";
jsonNode1 = objectMapper.readTree(JsonObject1);
jsonNode2 = objectMapper.readTree(jsonObject2);
System.out.println(jsonNode1.equals(jsonNode2));
}
@Test
public void compareTwoNestedJsonObjects() throws JsonMappingException, JsonProcessingException
{
// Nested json objects can also be compared with equals method
JsonObject1 = "{\r\n" +
" \"lastName\": \"Mahajan\",\r\n" +
" \"firstName\": \"Amod\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Katihar\",\r\n" +
" \"state\": \"Bihar\"\r\n" +
" }\r\n" +
"}";
jsonObject2 = "{\r\n" +
" \"lastName\": \"Mahajan\",\r\n" +
" \"firstName\": \"Amod\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Katihar\",\r\n" +
" \"state\": \"Bihar\"\r\n" +
" }\r\n" +
"}";
jsonNode1 = objectMapper.readTree(JsonObject1);
jsonNode2 = objectMapper.readTree(jsonObject2);
System.out.println(jsonNode1.equals(jsonNode2));
}
}
true true true
package CompareJSONUsingJackson;
import org.testng.annotations.Test;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
public class CompareJsonArrays {
String jsonArray1;
String jsonArray2;
ObjectMapper objectMapper;
JsonNode jsonNode1;
JsonNode jsonNode2;
@Test
public void compareTwoJsonArrays() throws JsonMappingException, JsonProcessingException
{
jsonArray1 = "[\r\n" +
" {\r\n" +
" \"lastName\": \"Mahajan\",\r\n" +
" \"firstName\": \"Amod\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Katihar\",\r\n" +
" \"state\": \"Bihar\"\r\n" +
" }\r\n" +
" },\r\n" +
" {\r\n" +
" \"lastName\": \"Animesh\",\r\n" +
" \"firstName\": \"Prashant\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Kolkata\",\r\n" +
" \"state\": \"WB\"\r\n" +
" }\r\n" +
" }\r\n" +
"]";
jsonArray2 = "[\r\n" +
" {\r\n" +
" \"lastName\": \"Mahajan\",\r\n" +
" \"firstName\": \"Amod\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Katihar\",\r\n" +
" \"state\": \"Bihar\"\r\n" +
" }\r\n" +
" },\r\n" +
" {\r\n" +
" \"lastName\": \"Animesh\",\r\n" +
" \"firstName\": \"Prashant\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Kolkata\",\r\n" +
" \"state\": \"WB\"\r\n" +
" }\r\n" +
" }\r\n" +
"]";
objectMapper = new ObjectMapper();
jsonNode1 = objectMapper.readTree(jsonArray1);
jsonNode2 = objectMapper.readTree(jsonArray2);
// Checking if both json objects are same
System.out.println(jsonNode1.equals(jsonNode2));
}
@Test
public void compareTwoJsonArraysWithDifferentOrderOfElements() throws JsonMappingException, JsonProcessingException
{
// Change in order of elements in array will impact and it will not be considered same
jsonArray1 = "[\r\n" +
" {\r\n" +
" \"lastName\": \"Mahajan\",\r\n" +
" \"firstName\": \"Amod\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Katihar\",\r\n" +
" \"state\": \"Bihar\"\r\n" +
" }\r\n" +
" },\r\n" +
" {\r\n" +
" \"lastName\": \"Animesh\",\r\n" +
" \"firstName\": \"Prashant\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Kolkata\",\r\n" +
" \"state\": \"WB\"\r\n" +
" }\r\n" +
" }\r\n" +
"]";
jsonArray2 = "[\r\n" +
" {\r\n" +
" \"lastName\": \"Animesh\",\r\n" +
" \"firstName\": \"Prashant\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Kolkata\",\r\n" +
" \"state\": \"WB\"\r\n" +
" }\r\n" +
" },\r\n" +
" {\r\n" +
" \"lastName\": \"Mahajan\",\r\n" +
" \"firstName\": \"Amod\",\r\n" +
" \"address\": {\r\n" +
" \"city\": \"Katihar\",\r\n" +
" \"state\": \"Bihar\"\r\n" +
" }\r\n" +
" }\r\n" +
"]";
jsonNode1 = objectMapper.readTree(jsonArray1);
jsonNode2 = objectMapper.readTree(jsonArray2);
System.out.println(jsonNode1.equals(jsonNode2));
}
}
true false
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