Spring MVC – Full java based config

Spring MCV is a very powerful and flexible framework for web application development. It doesn’t just implement the MVC pattern, it allows you to develop Rest web services.

This post presents a web project sample with a full java configuration using Spring MVC 4 and Servlet 3 api. The source code is available in this link.

This project implements client side for the persistence sample presented in Spring-Data-JPA article

1 – Add project dependencies

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>4.0.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>3.0.1</version>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-mapper-asl</artifactId>
    <version>1.9.13</version>
</dependency>

2 – Spring MVC config class

import org.springframework.context.annotation.*;
import org.springframework.context.support.ReloadableResourceBundleMessageSource;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;
import org.springframework.web.servlet.config.annotation.*;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@EnableWebMvc
@Configuration
@ComponentScan(basePackages = { "com.mycompany.myproject.web.controller" })
public class MvcConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    @Bean
    public InternalResourceViewResolver jspViewResolver() {
        InternalResourceViewResolver bean = new InternalResourceViewResolver();
        bean.setPrefix("/WEB-INF/views/");
        bean.setSuffix(".jsp");
        return bean;
    }

    @Bean(name = "multipartResolver")
    public CommonsMultipartResolver getMultipartResolver() {
        return new CommonsMultipartResolver();
    }

    @Bean(name = "messageSource")
    public ReloadableResourceBundleMessageSource getMessageSource() {
        ReloadableResourceBundleMessageSource resource = new ReloadableResourceBundleMessageSource();
        resource.setBasename("classpath:messages");
        resource.setDefaultEncoding("UTF-8");
        return resource;
    }

}

3 – Webapp initializer

With servlet 3 API you can use a class to configure your web project instead of the classic web.xml file.
You have to check if your application server or your servlet container supports servlet 3 spec. For Tomcat you can have this information in this link:
tomcat.apache.org/whichversion

import javax.servlet.ServletContext;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.filter.DelegatingFilterProxy;
import org.springframework.web.servlet.DispatcherServlet;

public class WebAppInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext container) {
        // Create the 'root' Spring application context
        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
        rootContext.register(ServiceConfig.class, JPAConfig.class, SecurityConfig.class);

        // Manage the lifecycle of the root application context
        container.addListener(new ContextLoaderListener(rootContext));

        // Create the dispatcher servlet's Spring application context
        AnnotationConfigWebApplicationContext dispatcherServlet = new AnnotationConfigWebApplicationContext();
        dispatcherServlet.register(MvcConfig.class);
            
        // Register and map the dispatcher servlet
        ServletRegistration.Dynamic dispatcher = container.addServlet("dispatcher", new DispatcherServlet(dispatcherServlet));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/");
        
    }

 }

4 – Model class.

public class User {
 
    private Long id;

    private String firstName;

    private String familyName;

    private String email;

    // add extra attributes
    	
    // add getters and setters
	
}

5 – Add view as jsp page
We create a usersView.jsp page with code source bellow to display users list.

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<div class="col-sm-offset-1 col-sm-10">

    <legend>
        <spring:message code="table.user.title" />
    </legend>

    <div>
        <table id="dataTable" class="table table-striped table-bordered">
            <thead>
                <tr>
                    <th><spring:message code="table.user.id" /></th>
                    <th><spring:message code="table.user.firstName" /></th>
                    <th><spring:message code="table.user.falilyName" /></th>
                    <th><spring:message code="table.user.email" /></th>
                </tr>
            <thead>
            <tbody>
                <c:forEach var="u" items="${usersModel}">
                    <tr>
                        <td>${u.id}</td>
                        <td>${u.firstName}</td>
                        <td>${u.familyName}</td>
                        <td>${u.email}</td>
                    <tr>
                </c:forEach>
            </tbody>
        </table>
    </div>
</div>

6 – Develop your controller

The @Controller annotation indicates that a particular class serves the role of a controller.
The @RequestMapping annotation is used to map a URL to either an entire class or a particular handler method.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.MessageSource;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

@Controller
public class UserController {

    @Autowired
    private UserService userService;
 
    /**
    * Request mapping for user
    */
    @RequestMapping(value = "users", method = RequestMethod.GET)
    public ModelAndView getUsersView() {
        ModelAndView mv= new ModelAndView("usersView");
        mv.addObject("usersModel", userService.findAll());
        return mv;
    }
    
    /**
    * Rest web service
    */
    @RequestMapping(value = "/usersList", method = RequestMethod.GET)
    public @ResponseBody List<UserDto> getUsersRest() {
        return userService.findAll();
    }
}

7 – Test web project
When building your project you may have maven error telling you that the web.xml file is missing.
You can fix it by configuring the maven war plugin as presented bellow.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <configuration>
        <failOnMissingWebXml>false</failOnMissingWebXml>
    </configuration>
</plugin>

• Test display users
  http://localhost:8080/myproject/users
  

• Test rest web service
  http://localhost:8080/myproject/usersList
  You will get json reponse.
  

  [
      {
          "id": 1,
          "firstName": "adminName",
          "familyName": "adminFamily",
          "email": "admin@maycompany.com",
          "phone": "0033 1 23 45 67 89",
          "language": "en",
          "login": "admin",
          "password": "admin",
          "burthDate": null,
          "authorities": [
              {"id": 3, "name": "user"},
              {"id": 2, "name": "technical user"},
              {"id": 1, "name": "admin"}
          ],
          "enabled": true,
          "pictureId": null,
          "authoritiesAsString": "user, technical user, admin"
      },
      ..........
  ]
  

Here’s the how to video created by Webucator.com. Check out their Spring training classes.

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