Spring MVC Concepts

Internal

• Spring Framework Concepts

To Process

TO PROCESS:

• https://docs.spring.io/spring-framework/docs/current/spring-framework-reference/web.html#spring-web
• https://spring.io/guides/gs/rest-service/
• https://spring.io/guides/gs/serving-web-content/
• https://spring.io/guides/tutorials/bookmarks/
• https://docs.spring.io/spring-boot/docs/2.0.5.RELEASE/reference/htmlsingle/#boot-features-developing-web-applications

Controller

A controller is a class that handles requests, fetches and processes data, and then responds with information of some sort. In case of a browser-facing application, a controller responds by optionally populating model data and passing the request to a view that produces HTML to be returned to the browser. In case of a REST application, the controller writes data directly into the body of the response. The view is indicated by its logical name, which is returned by the method.

A controller that forwards the request to a view for rendering:

@Controller
public class HomeController {

    @GetMapping("/")
    public String home() {

        // returns the view name
        return "home";
    }
}

Handler method.

@Controller @GetMapping

View

The view renders data into HTML format. The view is instantiated dynamically, and its implementation depends on the template engine that is available in the classpath. The template name is derived from the logical name by prefixing it with /templates and postfixing it with .html. Simply placing a <logical-view-name>.html under src/resources/templates makes the template-based view available.

Project Directory Layout

src/main/resource/static
src/main/resource/static/images
src/main/resource/templates

Testing MVC Applications

import org.springframework.test.web.servlet.MockMvc;
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;
import static org.hamcrest.Matchers.containsString;

@RunWith(SpringRunner.class)
@WebMvcTest(HomeController.class)
public class HomeControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    public void testHomePage() throws Exception {

        mockMvc.perform(get("/")).
                andExpect(status().isOk()).
                andExpect(view().name("home")).
                andExpect(content().string(containsString("Welcome to ...")));
    }
}

Spring MVC testing implies using @WebMvcTest. MockMvc mocks the mechanics of Spring MVC, instead of starting a full blown web server.

REST Clients

RestTemplate

TO PROCESS: https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#webmvc-resttemplate

POSTing Resource. Data

This overloaded version allows you to receive the newly created resource as a domain model object:

RestTemplate restTemplate = new RestTemplate();

MyResource model = new MyResource(...);

MyResource created = restTemplate.postForObject("http://localhost:8080/myresource", model, MyResource.class);