Spring Boot MockMVC Example

Automated testing plays role in building reliable applications. In Spring Boot, MockMvc allows us to test the web layer without starting the full HTTP server. With @AutoConfigureMockMvc, Spring Boot injects a MockMvc instance that we can use to simulate HTTP requests and verify responses.

What is MockMvc

• Part of Spring Test, MockMvc simulates HTTP requests to Spring MVC controllers.
• No real server is started; instead, it runs in-memory.
• Useful for controller layer tests with full Spring context.

Step-by-Step Implementation

Step 1. Create the project

Create a project using Spring Initializr and set the

• Project: Maven
• Language: Java
• Spring Boot: 3.x (e.g. 3.3.3)
• Packaging: Jar
• Java: 17
• Dependencies: Spring Web, Thymeleaf, Spring Boot DevTools (optional)

Download the generated zip and unzip/import it into your IDE as an existing Maven project.

Project Structure:

pom.xml

Step 2. Main Class

• Create WebAppMain.java to bootstrap the Spring Boot application.
• src->main->java->com->example->mockmvcdemo->WebAppMain.java

Step 3. Create Service Class

• Implement WelcomeService to provide business logic for greetings.
• src->main->java->com->example->mockmvcdemo->service->WelcomeService.java

Step 4. Create Controller

• Implement WelcomeMvcController with @GetMapping endpoints to render views and add model attributes.
• src->main->java->com->example->mockmvcdemo->controller->WelcomeMvcController.java

Step 5. Crteate Thymeleaf template

• Create simple HTML pages (welcome-page.html, event-page.html) to display dynamic content.
• src->main->resources->templates->welcome->page.html
• src->main->resources->templates->event-page.html

page.html

event-page.html

Note: If you plan to use slice tests (@WebMvcTest) you can omit templates in that setup; full-context tests with @SpringBootTest + view resolution require templates.

Step 6. Integration-style MockMvc tests

• Write WelcomeWebAppTest.java using @SpringBootTest and @AutoConfigureMockMvc to test the full web layer
• src->test->java->com->example->mockmvcdemo->WelcomeWebAppTest.java

Step 7. Faster slice test with @WebMvcTest

• Write faster unit-style tests using @WebMvcTest and @MockBean for controller layer isolation.
• src->test->java->com->example->mockmvcdemo->WelcomeControllerSliceTest.java

Step 8. Run Application

Start the application with mvn spring-boot:run and execute tests with mvn test or IDE run option.

mvn spring-boot:run

Testing in the Browser

http://localhost:8080/?name=Geeks

• The / endpoint in WelcomeMvcController is called.
• WelcomeService generates the greeting:

Welcome, Geeks to the world of programming!!!

• welcome-page.html renders the greeting dynamically.

Running Tests Using Maven

• Runs both integration tests (@SpringBootTest) and slice tests (@WebMvcTest).
• MockMvc simulates HTTP requests to controller endpoints.
• Verifies HTTP status, model attributes and view names.
• Test results are printed in the console.

Execute all tests with:

mvn test