Spring MVC

ServletDispatcher

ServletDispatcher

<web-app>
    <servlet>
        <servlet-name>example</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>example</servlet-name>
        <url-pattern>/example/*</url-pattern>
    </servlet-mapping>

</web-app>

ServletDispatcher

public class MyWebApplicationInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext container) {
        ServletRegistration.Dynamic registration =
             container.addServlet("dispatcher", new DispatcherServlet());
        registration.setLoadOnStartup(1);
        registration.addMapping("/example/*");
    }

}

ServletDispatcher

ServletDispatcher

<web-app>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/root-context.xml</param-value>
    </context-param>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

ServletDispatcher

ServletDispatcher

<web-app>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/root-context.xml</param-value>
    </context-param>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value></param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

Java configuration

public class MyWebApplicationInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext container) {
        XmlWebApplicationContext appContext = new XmlWebApplicationContext();
        appContext.setConfigLocation("/WEB-INF/spring/dispatcher-config.xml");

        ServletRegistration.Dynamic registration =
            container.addServlet("dispatcher", new DispatcherServlet(appContext));
        registration.setLoadOnStartup(1);
        registration.addMapping("/");
    }

}

Java configuration

public class MyWebApplicationInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext container) {
        XmlWebApplicationContext appContext = new XmlWebApplicationContext();
        appContext.setConfigLocation("/WEB-INF/spring/dispatcher-config.xml");

        ServletRegistration.Dynamic registration =
            container.addServlet("dispatcher", new DispatcherServlet(appContext));
        registration.setLoadOnStartup(1);
        registration.addMapping("/");
    }

}

Java configuration with XML context

public class MyWebAppInitializer extends AbstractDispatcherServletInitializer {

    @Override
    protected WebApplicationContext createRootApplicationContext() {
        return null;
    }

    @Override
    protected WebApplicationContext createServletApplicationContext() {
        XmlWebApplicationContext cxt = new XmlWebApplicationContext();
        cxt.setConfigLocation("/WEB-INF/spring/dispatcher-config.xml");
        return cxt;
    }

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

}

ServletDispatcher

  • HandlerMapping
  • HandlerAdapter
  • HandlerExceptionResolver
  • ViewResolver
  • LocaleResolver and LocaleContextResolver
  • ThemeResolver
  • MultipartResolver
  • FlashMapManager

ServletDispatcher.properties

# Default implementation classes for DispatcherServlet's strategy interfaces.
# Used as fallback when no matching beans are found in the DispatcherServlet context.
# Not meant to be customized by application developers.

org.springframework.web.servlet.LocaleResolver=org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver

org.springframework.web.servlet.ThemeResolver=org.springframework.web.servlet.theme.FixedThemeResolver

org.springframework.web.servlet.HandlerMapping=org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,\
	org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping

org.springframework.web.servlet.HandlerAdapter=org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,\
	org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,\
	org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter

org.springframework.web.servlet.HandlerExceptionResolver=org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerExceptionResolver,\
	org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver,\
	org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver

org.springframework.web.servlet.RequestToViewNameTranslator=org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator

org.springframework.web.servlet.ViewResolver=org.springframework.web.servlet.view.InternalResourceViewResolver

org.springframework.web.servlet.FlashMapManager=org.springframework.web.servlet.support.SessionFlashMapManager

Enabling Web MVC

@Configuration
@EnableWebMvc
public class WebConfig {

}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <mvc:annotation-driven/>

</beans>

Customizing configuration

@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {

    // Override configuration methods...

}

@Controller

@Controller
public class HelloWorldController {

    @RequestMapping("/helloWorld")
    public String helloWorld(Model model) {
        model.addAttribute("message", "Hello World!");
        return "helloWorld";
    }
}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="org.springframework.samples.petclinic.web"/>

    <!-- ... -->

</beans>

@Controller

@Controller
@RequestMapping("/appointments")
public class AppointmentsController {
    @Autowired
    private final AppointmentBook appointmentBook;

    @RequestMapping(method = RequestMethod.GET)
    public Map<String, Appointment> get() {
        return appointmentBook.getAppointmentsForToday();
    }

    @RequestMapping(path = "/{day}", method = RequestMethod.GET)
    public Map<String, Appointment> getForDay(@PathVariable @DateTimeFormat(iso=ISO.DATE) Date day, Model model) {
        return appointmentBook.getAppointmentsForDay(day);
    }

    @RequestMapping(path = "/new", method = RequestMethod.GET)
    public AppointmentForm getNewForm() {
        return new AppointmentForm();
    }

    @RequestMapping(method = RequestMethod.POST)
    public String add(@Valid AppointmentForm appointment, BindingResult result) {
        if (result.hasErrors()) {
            return "appointments/new";
        }
        appointmentBook.addAppointment(appointment);
        return "redirect:/appointments";
    }
}

URI Template Patterns

@RequestMapping(path="/owners/{ownerId}", method=RequestMethod.GET)
public String findOwner(@PathVariable String ownerId, Model model) {
    Owner owner = ownerService.findOwner(ownerId);
    model.addAttribute("owner", owner);
    return "displayOwner";
}
@RequestMapping(path="/owners/{ownerId}", method=RequestMethod.GET)
public String findOwner(@PathVariable("ownerId") String theOwner, Model model) {
    // implementation omitted
}
@RequestMapping(path="/owners/{ownerId}", method=RequestMethod.GET)
public String findOwner(@PathVariable String ownerId, Model model) {
    // implementation omitted
}

Multiple @PathVariable

@RequestMapping(path="/owners/{ownerId}/pets/{petId}", method=RequestMethod.GET)
public String findPet(@PathVariable String ownerId, @PathVariable String petId, Model model) {
    Owner owner = ownerService.findOwner(ownerId);
    Pet pet = owner.getPet(petId);
    model.addAttribute("pet", pet);
    return "displayPet";
}
@RequestMapping(path="/owners/{ownerId}/pets/{petId}", method=RequestMethod.GET)
public String findPet(@PathVariable Map<String, String> pathVariables, Model model) {
    Owner owner = ownerService.findOwner(pathVariables.get("ownerId"));
    Pet pet = owner.getPet(pathVariables("petId"));
    model.addAttribute("pet", pet);
    return "displayPet";
}

Regular Expressions in  @PathVariable

@RequestMapping("/spring-web/{symbolicName:[a-z-]+}-{version:\\d\\.\\d\\.\\d}{extension:\\.[a-z]+}")
    public void handle(@PathVariable String version, @PathVariable String extension) {
        // ...
    }
}

Parametrized Paths

@RequestMapping("/spring-web/${someParameterFromPropertyFile}/*")
    public void handle() {
        // ...
    }
}

Suffix Pattern Matching

  • by default spring applies .* pattern suffix
  • /person → /person.json

Producible Media Types

@Controller
@RequestMapping(path = "/pets/{petId}", method = RequestMethod.GET,
  produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
@ResponseBody
public Pet getPet(@PathVariable String petId, Model model) {
    // implementation omitted
}

Request Parameters and Headers Values

@Controller
@RequestMapping("/owners/{ownerId}")
public class RelativePathUriTemplateController {

    @RequestMapping(path = "/pets/{petId}", method = RequestMethod.GET, params="myParam=myValue")
    public void findPet(@PathVariable String ownerId, @PathVariable String petId, Model model) {
        // implementation omitted
    }

}
@Controller
@RequestMapping("/owners/{ownerId}")
public class RelativePathUriTemplateController {

    @RequestMapping(path = "/pets", method = RequestMethod.GET, headers="!myHeader")
    public void findPet(@PathVariable String ownerId, @PathVariable String petId, Model model) {
        // implementation omitted
    }

}

Supported method argument types

  • ServletRequest or HttpServlet Request (and responses)
  • HttpSession (from Servlet API)
  • java.io.InputStream / java.io.Reader (raw stream/reader exposed by Servlet API)
  • java.io.OutputStream / java.io.Writer

Supported method argument types

  • java.util.TimeZone (java 6+)
  • java.time.ZoneId (java 8)
  • java.util.Locale

Request body

@RequestMapping(path = "/something", method = RequestMethod.PUT)
public void handle(@RequestBody String body, Writer writer) throws IOException {
    writer.write(body);
}

Response body

@RequestMapping(path = "/something", method = RequestMethod.PUT)
@ResponseBody
public String helloWorld() {
    return "Hello World";
}

Using HttpEntity

@RequestMapping("/something")
public ResponseEntity<String> handle(HttpEntity<byte[]> requestEntity) throws UnsupportedEncodingException {
    String requestHeader = requestEntity.getHeaders().getFirst("MyRequestHeader"));
    byte[] requestBody = requestEntity.getBody();

    // do something with request header and body

    HttpHeaders responseHeaders = new HttpHeaders();
    responseHeaders.set("MyResponseHeader", "MyValue");
    return new ResponseEntity<String>("Hello World", responseHeaders, HttpStatus.CREATED);
}

Creating REST Controller

@RestController
public class HelloWorldRestController {
 
    @RequestMapping("/hello/{player}")
    public Message message(@PathVariable String player) {
 
        Message msg = new Message(player, "Hello " + player);
        return msg;
    }
 
}

Cookies

@RequestMapping("/displayHeaderInfo.do")
public void displayHeaderInfo(@CookieValue("JSESSIONID") String cookie) {
    //...
}

Headers

@RequestMapping("/displayHeaderInfo.do")
public void displayHeaderInfo(@RequestHeader("Accept-Encoding") String encoding,
        @RequestHeader("Keep-Alive") long keepAlive) {
    //...
}

http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/http/HttpHeaders.html

Exceptions handling

@Controller
public class SimpleController {

    // @RequestMapping methods omitted ...

    @ExceptionHandler(IOException.class)
    public ResponseEntity<String> handleIOException(IOException ex) {
        // this will be executed on IOException
        return responseEntity;
    }

}

Exceptions handling

public interface HandlerExceptionResolver {
	ModelAndView resolveException(
			HttpServletRequest request,
			HttpServletResponse response, Object handler, Exception ex);
}
  • DefaultHandlerExceptionResolver is default implementation
  • Maps Exceptions to HTTP error codes

DefaultHandlerException

Resolver

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Spring MVC

By Artur Owczarek

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Spring MVC

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