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Table of contents
REST Assured
Writing Response in a Text File
Frequently Asked Questions
How do you pass JSON payload in Rest assured?
Where is REST assured used?
What is the difference between PATCH, PUT and POST in Rest assured?
Can we delete a resource using the POST method?
Why is Maven used in projects?
Last Updated: Mar 27, 2024

REST Assured – Writing Response in a Text File

Author Kanak Rana
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Ashwin Goyal
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Hello Ninjas! Welcome to this blog, where we discuss Rest Assured – Writing Response in a Text File.

REST Assured – Writing Response in a Text File

Here in this article, we have covered the definitions of REST assured, know about writing a response in a text file with the help of code, and later explanation is given to understand what is happening in the code. 

Let's start our topic, and REST Assured – Writing Response in a Text File, by first knowing about REST Assured.

REST Assured

Rest Assured is a Java library that allows you to test and validate REST(Representational State Transfer) services, APIs(application program interface), and Web Services.

Previously, API testing was more complex than with Ruby and Groovy. It provides that simplicity and flexibility in Java.

REST Assured

It is a platform that is open source. It is based on HTTP Builder and can handle POST, GET, PUT, DELETE, OPTIONS, PATCH, and HEAD requests.

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Writing Response in a Text File

Testing and validating REST resources in any application, especially in Java, is complex and confusing. REST Assured simplifies things by allowing us to use REST-Assured Java APIs to send requests and validate anything in the Response.

However, while performing this simple request and response, we frequently run into the problem of figuring out how to configure REST Assured logs to be written to a file or test logs rather than printed to the console.

Writing the same requests and responses to the log file will aid us in future debugging or a better understanding of our test flow.

Now, let us implement code to log the Response of the POST request (Let's Write First POST Request in REST Assured) into a text file.


package javaPackageName;
import io.restassured.RestAssured;
import org.testng.annotations.Test;
import io.restassured.http.ContentType;
import io.restassured.response.Response;
import io.restassured.response.ValidatableResponse;
import io.restassured.specification.RequestSpecification;
 public class POSTRequest {
 	public void post_request() throws FileNotFoundException
 		String jsonString = "{\"name\" : \"kanak\",\"password\" : \"kanak123\"}";
 		// Construct a request specification
 		RequestSpecification request= RestAssured.given();
 		// Setting content type to specify the format in which the request payload will be sent.
 		// Adding URI
 		// Adding body as string
 		// Calling POST method on URI. After hitting, we get Response
 		Response response =;
 		// Printing Response as string
 		try {
 			PrintStream out = new PrintStream(new File("src/main/resources/targetFile.txt"));
 		catch(FileNotFoundException fx) 
 		// Get Validatable response to perform validation
 		ValidatableResponse validatableResponse = response.then();   
 		// Validate status code as 201




In the above code, we created a method called "post_request". Under this method, we defined a JSON string variable of string type to store JSON values. Then we constructed a request specification, set the content type, and added URI. After we added URI, we added the body as a string. Then we called the POST method on URI, printed the Response, wrote the response to a text file(targetFile.txt), and performed validation.

Frequently Asked Questions

How do you pass JSON payload in Rest assured?

First, the contents of the file should be converted to a string. Then we should read the file content and convert it to Byte data type. Once the entire data is converted to Byte, we should finally convert it to string. We shall utilize an external JSON file as a payload for executing a POST request.

Where is REST assured used?

Rest Assured is used to validate REST APIs using the Java library. The Java library acts as a headless client to interact with Rest web services. It is based on the Rest Assured library and can validate the server's HTTP responses.

What is the difference between PATCH, PUT and POST in Rest assured?

POST is always for creating a resource (it does not matter if it was duplicated), and PUT is checking if the resource exists and then updating it, or else creating a new resource. PATCH is always for updating a resource.

Can we delete a resource using the POST method?

We may use the POST method to create, update and delete resources, but this is considered an inappropriate design. The different HTTP verbs standardize modern ways of creating REST APIs.

Why is Maven used in projects?

Maven primarily assists in downloading dependencies, which are libraries or JAR files, for Java-based applications.


In this blog, we have learned about Rest assured – Writing Response in a Text File. We have covered the Rest assured, writing Response in a text file with java code.

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