MVC on the WEB

~$> whoami

Ioan Marius Curelariu

SDE at Website Analytics

Amazon Development Center Romania

The Server Side Story

The Server Side Story

Elastic Beanstalk

The Spring Framework

• First described in 2002, in “Expert One-on-One J2EE Design and Development” book, by Rod Johnson.

Spring Container

Spring Container

Spring Container

Spring Modules

Core

AOP

Data Access Objects

Object Relational Mapping

Context

Web

MVC

Model View Controller

Controller

View

Model User

Uses

Manipulates

Updates Sees

Spring MVC Architecture

Controller

Handler Mapping

View Resolver

View

Dispatcher Servlet

1. Request

Model and View

Application Logic

Application Data

2

3

4

5 6

TodoMVC Data Model

Todo Todos

TodoSpringMVC Data Model

Todo Todos

User Users

TodoSpringMVC Data Model

TodosManager Todos

User UsersManager

Spring MVC Architecture

Controller

Handler Mapping

View Resolver

View

Dispatcher Servlet

1. Request

Model and View

Application Logic

Application Data

2

3

4

5 6

DispatcherServlet

In /WEB-INF/web.xml <servlet> <servlet-name>appServlet</servlet-name> <servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name> appServlet </servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping>

ContextLoaderListener

In /WEB-INF/web.xml <context-param> <param-name> contextConfigLocation </param-name> <param-value> /WEB-INF/spring/root-context.xml </param-value> </context-param> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener>

Essential Configuration Declare the controllers and other components (appServlet-context.xml)

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="locations"> <value>classpath:todospringmvc.properties</value> </property> </bean> <context:component-scan base-package=“com.amazon.todo.web”/>

Essential Configuration Resolve JSP Views

<bean name=“viewResolver” class=“org.springframework.web.servlet.view.InternalResourceView Resolver”> <property name=“prefix” value=“/WEB-INF/views”/> <property name=“suffix” value=“.jsp”/> </bean>

Essential Configuration Handle annotation-driven request mappings <mvc:annotation-driven/>

Spring MVC Architecture

Controller

Handler Mapping

View Resolver

View

Dispatcher Servlet

1. Request

Model and View

Application Logic

Application Data

2

3

4

5 6

SpringMVC Controller

• Configured using java annotations

– @Controller

– @RequestMapping

• Simple JavaBeans

• Multiple handler mappings

@Controller public class HomeController { … @ModelAttribute(value = "userName") public String getUserName(Principal user) { return user.getName(); } @RequestMapping(value = "/", method = RequestMethod.GET) public String home(Locale locale, Model model) { DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG, locale); String formattedDate = dateFormat.format(new Date()); model.addAttribute("serverTime", formattedDate ); return "home"; } }

@Controller @RequestMapping(“/register”)

public class RegistrationController {

@RequestMapping(method = RequestMethod.POST)

public String registerUser(TodoUser todoUser) {

return “redirect:/”;

}

@RequestMapping(method = RequestMethod.POST)

public String register(TodoUser todoUser) {

return “register”;

}

@RequestMapping(value = “/validateUsername")

public @ResponseBody String suggestUsername(@RequestParam String username) {

return username;

}

}

@Controller @RequestMapping(value = "/todos", produces = "application/json") public class TodosController { … @RequestMapping( value = "/{todoItemId}", method = RequestMethod.PUT, consumes = "application/json" ) @ResponseBody public TodoItem alterTodo(@PathVariable String todoItemId, @RequestBody TodoItem todoItem) { … } }

Spring MVC Parameters & Return types • Parameters can be

– HttpServletRequest / HttpServletResponse / HttpSession

– WebRequest

– InputStream / OutputStream

– @RequestParam / @PathVariable / @RequestBody / @CookieValue

• Return types can be

– ModelAndView / Model / Map

– View Object

– String (logical view name)

– Void

SpringMVC Views

• Integrates with many existing technologies

• Out of the box support for JSP & JSTL

Spring MVC Views

JSON

Negotiating Content

Request

ContentNegociatingViewResolver

Other Spring MVC Features

• Exception Handling

• Localization Support

• Theme Handling

• Multipart (file upload) support

• Asynchronous Request Processing

• Testability

What we have done …

Hosting ...

First Beanstalk Application

Basic Application Informations

Application Environment Details

Application Configuration Details

Amazon RDS Instance Configuration

Configuration Summary

Application Console

Deploying a New Version

Thank you!...

http://amazonacademytodos.elasticbeanstalk.com