Spring MockMvc tutorial

last modified October 18, 2023

Spring MockMvc tutorial shows how to test Spring MVC application with MockMvc.

Spring is a popular Java application framework for creating enterprise applications.

MockMvc

MockMvc is defined as a main entry point for server-side Spring MVC testing. Tests with MockMvc lie somewhere between between unit and integration tests.

Spring MockMvc example

The following application uses MockMvc to test a Spring MVC application. We create a test for a template and for a RESTful controller method.

pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ ├───config │ │ │ MyWebInitializer.java │ │ │ WebConfig.java │ │ └───controller │ │ MyController.java │ ├───resources │ └───webapp │ └───WEB-INF │ └───templates │ index.html └───test └───java └───com └───zetcode └───controller MyControllerTest.java

This is the project structure.

pom.xml

<?xml version=“1.0” encoding=“UTF-8”?> <project xmlns=“http://maven.apache.org/POM/4.0.0" xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=“http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>

<groupId>com.zetcode</groupId>
<artifactId>mockmvcex</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>17</maven.compiler.source>
    <maven.compiler.target>17</maven.compiler.target>
    <spring-version>5.3.23</spring-version>
</properties>

<dependencies>

    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.4.0</version>
    </dependency>

    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring-version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>${spring-version}</version>
    </dependency>

    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf-spring5</artifactId>
        <version>3.0.11.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.thymeleaf</groupId>
        <artifactId>thymeleaf</artifactId>
        <version>3.0.11.RELEASE</version>
    </dependency>

</dependencies>

<build>
    <plugins>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>3.3.2</version>
        </plugin>

    </plugins>
</build>

</project>

In the pom.xml file we have the following dependencies: logback-classic, javax.servlet-api, junit, spring-webmvc, spring-test, thymeleaf-spring5 and thymeleaf.

com/zetcode/config/MyWebInitializer.java

package com.zetcode.config;

import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

@Configuration public class MyWebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

@Override
protected Class<?>[] getRootConfigClasses() {
    return null;
}

@Override
protected Class<?>[] getServletConfigClasses() {
    
    return new Class[]{WebConfig.class};
}

@Override
protected String[] getServletMappings() {
    
    return new String[]{"/"};
}

}

MyWebInitializer registers the Spring DispatcherServlet, which is a front controller for a Spring web application.

@Override protected Class<?>[] getServletConfigClasses() {

return new Class[]{WebConfig.class};

}

The getServletConfigClasses returns a web configuration class.

com/zetcode/config/WebConfig.java

package com.zetcode.config;

import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.ViewResolver; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.ViewResolverRegistry; import org.thymeleaf.spring5.SpringTemplateEngine; import org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver; import org.thymeleaf.spring5.view.ThymeleafViewResolver;

@Configuration @EnableWebMvc @ComponentScan(basePackages = {“com.zetcode”}) public class WebConfig {

@Autowired
private ApplicationContext applicationContext;

@Bean
public SpringResourceTemplateResolver templateResolver() {

    var templateResolver = new SpringResourceTemplateResolver();

    templateResolver.setApplicationContext(applicationContext);
    templateResolver.setPrefix("/WEB-INF/templates/");
    templateResolver.setSuffix(".html");

    return templateResolver;
}

@Bean
public SpringTemplateEngine templateEngine() {

    var templateEngine = new SpringTemplateEngine();
    templateEngine.setTemplateResolver(templateResolver());
    templateEngine.setEnableSpringELCompiler(true);

    return templateEngine;
}

@Bean
public ViewResolver viewResolver() {

    var resolver = new ThymeleafViewResolver();
    var registry = new ViewResolverRegistry(null, applicationContext);

    resolver.setTemplateEngine(templateEngine());
    registry.viewResolver(resolver);

    return resolver;
}

}

The WebConfig enables Spring MVC annotations with @EnableWebMvc and configures component scanning for the com.zetcode package. It sets up the Thymeleaf engine.

com/zetcode/controller/MyController.java

package com.zetcode.controller;

import org.springframework.http.MediaType; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.ResponseBody;

import java.time.LocalDateTime;

@Controller public class MyController {

@GetMapping(value = "/", produces = MediaType.TEXT_HTML_VALUE)
public String home(Model model) {

    model.addAttribute("now", LocalDateTime.now());

    return "index";
}

@GetMapping(value = "/message", produces = MediaType.TEXT_PLAIN_VALUE)
@ResponseBody
public String message() {

    return "Hello there!";
}

}

MyController provides two handler methods. The home method return a view with a single attribute and the message method returns a plain text message. In our tests we test these two methods.

WEB-INF/templates/index.html

<!DOCTYPE html> <html xmlns:th=“http://www.thymeleaf.org”> <head> <meta charset=“UTF-8”> <title>Home page</title> </head> <body>

<p> Today is: <span th:text="${now}"></span> </p>

</body> </html>

This is the index.html view.

com/zetcode/controller/MyControllerTest.java

package com.zetcode.controller;

import org.junit.Before; import org.junit.Test; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.result.MockMvcResultHandlers; import org.springframework.test.web.servlet.setup.MockMvcBuilders; import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get; import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content; import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status; import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.view;

public class MyControllerTest {

private MockMvc mockMvc;

@Before
public void setup() {
    this.mockMvc = MockMvcBuilders.standaloneSetup(new MyController()).build();
}

@Test
public void testHomePage() throws Exception {
    this.mockMvc.perform(get("/"))
            .andExpect(status().isOk())
            .andExpect(view().name("index"))
            .andDo(MockMvcResultHandlers.print())
            .andReturn();
}

@Test
public void testMessagePage() throws Exception {
    this.mockMvc.perform(get("/message")).andExpect(status().isOk())
            .andExpect(content().string("Hello there!"));
}

}

MyControllerTest tests the two handlers.

private MockMvc mockMvc;

@Before public void setup() { this.mockMvc = MockMvcBuilders.standaloneSetup(new MyController()).build(); }

We set up the MockMvc. We add the MyController to the standalone setup. The MockMvcBuilders.standaloneSetup allows to register one or more controllers without the need to use the full WebApplicationContext.

@Test public void testHomePage() throws Exception { this.mockMvc.perform(get(”/”)) .andExpect(status().isOk()) .andExpect(view().name(“index”)) .andDo(MockMvcResultHandlers.print()); }

We test the home page. We verify the status and the returned view name. We also print the result.

@Test public void testMessagePage() throws Exception { this.mockMvc.perform(get("/message”)).andExpect(status().isOk()) .andExpect(content().string(“Hello there!”)); }

We test the message page. Since it is a RESTful method, we verify the status and the returned string.

$ mvn -q test

We run the tests with mvn -q test.

In this article we have created tests for Spring MVC with MockMvc.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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