Julian Jupiter - Blog - Simple Spring MVC Application with Java Configuration

Introduction

This is a simple Spring MVC application with Java configuration instead of XML.

Our application won’t require an application server to deploy to. We are going to use Embdded Tomcat. Also, the application will be packaged to singler executable JAR, including dependencies. We call this Fat JAR or Uber JAR. It is similar to Spring Boot. To achieve it, we’ll use Apache Maven Shade Plugin.

We’ll also use JSP as our template engine.

For this project, we create project foler SpringMVCGreetingsApp.

Requirements

Java 11 - OpenJDK, GraalVM, Zulu Builds of OpenJDK, Amazon Corretto, SapMachine, Liberica JDK
Maven - you must have installed Maven or create Maven wrapper.
IDE - Intellij IDEA, NetBeans, Eclipse

Project Structure

    SpringMVCGreetingsApp
    └── src
        └── main
            └── java
                └── com
                    └── julianjupiter
                        └── springmvcgreetings
                            └── configuration
                            └── controller
                            └── server
            └── resources
            └── webapp
                └── assets
                    └── css
                    └── js
                └── WEB-INF
                    └── views
                        └── greetings
                        └── home
                        └── includes
    └── pom.xml

Maven Dependencies

Copy and paste the following to your pom.xml:

<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>io.github.julianjupiter</groupId>
	<artifactId>SpringMVCGreetingsApp</artifactId>
	<version>1.0.0-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>SpringMVCGreetingsApp</name>
	<description>Spring MVC Application with Java configuration.</description>

	<properties>
		<failOnMissingWebXml>false</failOnMissingWebXml>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<maven.compiler.source>11</maven.compiler.source>
		<maven.compiler.target>11</maven.compiler.target>
		<tomcat.version>9.0.37</tomcat.version>
		<spring.version>5.2.8.RELEASE</spring.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.apache.tomcat.embed</groupId>
			<artifactId>tomcat-embed-core</artifactId>
			<version>${tomcat.version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.tomcat.embed</groupId>
			<artifactId>tomcat-embed-jasper</artifactId>
			<version>${tomcat.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>jakarta.servlet</groupId>
			<artifactId>jakarta.servlet-api</artifactId>
			<version>4.0.4</version>
		</dependency>
		<dependency>
			<groupId>jakarta.servlet.jsp</groupId>
			<artifactId>jakarta.servlet.jsp-api</artifactId>
			<version>2.3.6</version>
		</dependency>
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>jstl</artifactId>
			<version>1.2</version>
		</dependency>
	</dependencies>

	<build>
		<resources>
			<resource>
				<directory>src/main/webapp</directory>
				<targetPath>META-INF/resources</targetPath>
			</resource>
		</resources>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-shade-plugin</artifactId>
				<version>3.2.4</version>
				<configuration>
					<createDependencyReducedPom>true</createDependencyReducedPom>
					<filters>
						<filter>
							<artifact>*:*</artifact>
							<excludes>
								<exclude>META-INF/*.SF</exclude>
								<exclude>META-INF/*.DSA</exclude>
								<exclude>META-INF/*.RSA</exclude>
							</excludes>
						</filter>
					</filters>
				</configuration>
				<executions>
					<execution>
						<phase>package</phase>
						<goals>
							<goal>shade</goal>
						</goals>
						<configuration>
							<createDependencyReducedPom>false</createDependencyReducedPom>
							<transformers>
								<transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
								<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
									<mainClass>com.julianjupiter.springmvcgreetings.SpringMVCGreetingsApplication</mainClass>
								</transformer>
							</transformers>
						</configuration>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>
</project>

Codes

Add Server

Since we’re using Embedded Tomcat, we’ll create our own server programmatically.

Server.java

package com.julianjupiter.springmvcgreetings.server;

public interface Server {
	void run(String[] args);

	static Server newServer() {
		return new TomcatServer();
	}
}

TomcatServer.java

package com.julianjupiter.springmvcgreetings.server;

import org.apache.catalina.Context;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.WebResourceRoot;
import org.apache.catalina.startup.Tomcat;
import org.apache.catalina.webresources.StandardRoot;

import java.io.File;
import java.lang.System.Logger;

class TomcatServer implements Server {

	private static final Logger LOGGER = System.getLogger(TomcatServer.class.getName());

	private static final String DEFAULT_HOST = "localhost";
	private static final int DEFAULT_PORT = 8080;
	private static final String DEFAULT_CONTEXT_PATH = "/";
	private static final String DOC_BASE = ".";
	private static final String ADDITION_WEB_INF_CLASSES = "src/main/";
	private static final String WEB_APP_MOUNT = "/WEB-INF/classes";
	private static final String INTERNAL_PATH = "/";

	@Override
	public void run(String[] args) {
		int port = this.port(args);
		Tomcat tomcat = this.tomcat(port);

		try {
			tomcat.start();
		} catch (LifecycleException exception) {
			LOGGER.log(Logger.Level.ERROR, exception.getMessage());
			LOGGER.log(Logger.Level.ERROR, "Exit...");
			System.exit(1);
		}

		LOGGER.log(Logger.Level.INFO, "Application started with URL {}.", DEFAULT_HOST + ":" + port + DEFAULT_CONTEXT_PATH);
		LOGGER.log(Logger.Level.INFO,"Hit Ctrl+D or Ctrl+C to stop it...");
		tomcat.getServer().await();
	}

	private int port(String[] args) {
		if (args.length > 0) {
			String port = args[0];
			try {
				return Integer.valueOf(port);
			} catch (NumberFormatException exception) {
				LOGGER.log(Logger.Level.ERROR, "Invalid port number argument {}", port, exception);
			}
		}

		return DEFAULT_PORT;
	}

	private Tomcat tomcat(int port) {
		Tomcat tomcat = new Tomcat();
		tomcat.setHostname(DEFAULT_HOST);
		tomcat.getHost().setAppBase(DOC_BASE);
		tomcat.setPort(port);
		tomcat.getConnector();
		this.context(tomcat);

		return tomcat;
	}

	private Context context(Tomcat tomcat) {
		Context context = tomcat.addWebapp("", DOC_BASE);
		File classes = new File(ADDITION_WEB_INF_CLASSES);
		String base = classes.getAbsolutePath();
		WebResourceRoot resources = new StandardRoot(context);
		context.setResources(resources);

		return context;
	}
}

Add Launcher

SpringMVCGreetingsApplication.java

package com.julianjupiter.springmvcgreetings;

import com.julianjupiter.springmvcgreetings.server.Server;

public class SpringMVCGreetingsApplication {
    public static void main(String[] args) {
        Server.newServer().run(args);
    }
}

Add Configuration

We’ll create our configuration using Java.

ApplicationWebConfiguration.java

package com.julianjupiter.springmvcgreetings.configuration;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.JstlView;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.julianjupiter.springmvcgreetings")
public class ApplicationWebConfiguration implements WebMvcConfigurer {

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

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        registry.jsp("/WEB-INF/views/", ".jsp")
                .viewClass(JstlView.class);
    }

}

ApplicationInitializer.java

package com.julianjupiter.springmvcgreetings.configuration;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class ApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

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

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

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

}

Add Controller

We’ll create only two (2) controllers - for index/home and greetings.

HomeController.java

package com.julianjupiter.springmvcgreetings.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.http.HttpServletRequest;
import java.lang.System.Logger;

@Controller
public class HomeController {

    private static final Logger LOGGER = System.getLogger(GreetingsController.class.getName());

    @RequestMapping(value = {"/", "/home"}, method = RequestMethod.GET)
    public String index(HttpServletRequest request, Model model) {
        LOGGER.log(Logger.Level.INFO, "URL: " + request.getRequestURL().toString());

        model.addAttribute("pageTitle", "Home");
        model.addAttribute("messageTitle", "Spring MVC Greetings Application");
        model.addAttribute("messageBody", "Welcome to Spring MVC Greetings Application!");

        return "home/index";
    }
}

GreetingsController.java

package com.julianjupiter.springmvcgreetings.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.http.HttpServletRequest;
import java.lang.System.Logger;

@Controller
public class GreetingsController {

    private static final Logger LOGGER = System.getLogger(GreetingsController.class.getName());

    @RequestMapping(value = {"/greetings"}, method = RequestMethod.GET)
    public String index(HttpServletRequest request, Model model) {
        LOGGER.log(Logger.Level.INFO, "URL: " + request.getRequestURL().toString());

        model.addAttribute("pageTitle", "Greetings");
        model.addAttribute("messageTitle", "Hello world!");
        model.addAttribute("messageBody", "Hello world! Welcome to Spring MVC!");

        return "greetings/index";
    }

}

Add Static Assets

We’ll be using Bootstrap CSS framework. I only include bootstrap.min.css, bootstrap.min.js, jquery-3.5.1.slim.min.js, and popper.min.js.

I also have minimal custom CSS style, application.css:

body {
  padding-top: 4.5rem;
}

footer {
   bottom:0;
   width:100%;
}

Add JSP templates

includes

head.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
<jsp:useBean id="date" class="java.util.Date" />
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
        <meta name="description" content="Spring MVC Application with Java configuration">
        <meta name="author" content="Julian Jupiter">
        <title>Spring MVC Greetings Application &mdash; ${pageTitle}</title>

        <!-- Bootstrap core CSS -->
        <link href="${pageContext.request.contextPath}/assets/css/bootstrap.min.css" rel="stylesheet">

        <!-- Custom styles for this template -->
        <link href="${pageContext.request.contextPath}/assets/css/application.css" rel="stylesheet">
    </head>
    <body>

header.jsp

        <nav class="navbar navbar-expand-md navbar-dark fixed-top bg-dark">
          <a class="navbar-brand" href="${pageContext.request.contextPath}/">Spring MVC Greetings Application</a>
          <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
          </button>
          <div class="collapse navbar-collapse" id="navbarCollapse">
            <ul class="navbar-nav mr-auto">
              <li class="${pageTitle == 'Home' ? 'nav-item active': 'nav-item'}">
                <a class="nav-link" href="${pageContext.request.contextPath}/">Home <span class="sr-only">(current)</span></a>
              </li>
              <li class="${pageTitle == 'Greetings' ? 'nav-item active': 'nav-item'}">
                <a class="nav-link" href="${pageContext.request.contextPath}/greetings">Greetings</a>
              </li>
            </ul>
          </div>
        </nav>
        <main role="main" class="flex-shrink-0">
            <div class="container">

footer.jsp

            </div>
        </main>
        <footer class="footer position-absolute mt-auto py-3">
            <div class="container">
                <div class="row">
                    <div class="col">
                        <p class="text-muted text-center">&copy; <a href="https://julianjupiter.com"><fmt:formatDate value="${date}" pattern="yyyy" /> Julian Jupiter</a></p>
                    </div>
                </div>
            </div>
        </footer>
        <!-- Bootstrap core JavaScript
        ================================================== -->
        <!-- Placed at the end of the document so the pages load faster -->
        <script src="${pageContext.request.contextPath}/assets/js/jquery-3.5.1.slim.min.js"></script>
        <script src="${pageContext.request.contextPath}/assets/js/popper.min.js"></script>
        <script src="${pageContext.request.contextPath}/assets/js/bootstrap.min.js"></script>
    </body>
</html>

home

index.jsp

<%@ include file="../includes/head.jsp" %>
<%@ include file="../includes/header.jsp" %>
    <div class="jumbotron">
        <h2>${messageTitle}</h2>
        <p>${messageBody}</p>
        <p><a class="btn btn-primary btn-lg" href="${pageContext.request.contextPath}/greetings" role="button">Go to greetings &raquo;</a></p>
    </div>
<%@ include file="../includes/footer.jsp" %>

greetings

index.jsp

<%@ include file="../includes/head.jsp" %>
<%@ include file="../includes/header.jsp" %>
    <div class="jumbotron">
        <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#greetings">Click me &raquo;</button>
        <div id="greetings" class="modal fade" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
            <div class="modal-dialog">
                <div class="modal-content">
                    <div class="modal-header">
                        <h5 class="modal-title" id="myModalLabel">${messageTitle}</h5>
                        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                   </div>
                    <div class="modal-body">
                        <p>${messageBody}</p>
                    </div>
                    <div class="modal-footer">
                        <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                    </div>
                </div>
            </div>
        </div>
    </div>
<%@ include file="../includes/footer.jsp" %>

Build Application

To build our Fat JAR:

$ mvn package

If you’re using Maven wrapper:

$ ./mvnw package

Above command generates executable JAR inside target folder with file name SpringMVCGreetingsApp-1.0.0-SNAPSHOT.jar.

Run Application

$ java -jar ./target/SpringMVCGreetingsApp-1.0.0-SNAPSHOT.jar

Above command logs the following in the console:

Jul 26, 2020 7:34:44 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-nio-8080"]
Jul 26, 2020 7:34:45 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service [Tomcat]
Jul 26, 2020 7:34:45 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet engine: [Apache Tomcat/9.0.37]
Jul 26, 2020 7:34:45 PM org.apache.catalina.startup.ContextConfig getDefaultWebXmlFragment
INFO: No global web.xml found
Jul 26, 2020 7:34:48 PM org.apache.catalina.core.ApplicationContext log
INFO: 1 Spring WebApplicationInitializers detected on classpath
Jul 26, 2020 7:34:48 PM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring DispatcherServlet 'dispatcher'
Jul 26, 2020 7:34:48 PM org.springframework.web.servlet.FrameworkServlet initServletBean
INFO: Initializing Servlet 'dispatcher'
Jul 26, 2020 7:34:48 PM org.springframework.web.servlet.FrameworkServlet initServletBean
INFO: Completed initialization in 660 ms
Jul 26, 2020 7:34:48 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
Jul 26, 2020 7:34:48 PM com.julianjupiter.springmvcgreetings.server.TomcatServer run
INFO: Application started with URL {}.
Jul 26, 2020 7:34:48 PM com.julianjupiter.springmvcgreetings.server.TomcatServer run
INFO: Hit Ctrl+D or Ctrl+C to stop it...

Embedded Tomcat listens on port 8080.

View Application in the browser

Open your browser and point to http://localhost:8080.

Screenshots

Home Page

Greetings Page

Conclusion

We’re able to create a Spring MVC application with Java configuration, no XML.

We build this application into a single JAR file, called Uber or Fat JAR; no need for standalone application server.

Clone the source

GitHub Source

$ git clone https://github.com/julianjupiter/SpringMVCGreetingsApp
$ cd SpringMVCGreetingsApp
$ ./mvnw clean package && java -jar ./target/SpringMVCGreetingsApp-1.0.0-SNAPSHOT.jar

Simple Spring MVC Application with Java Configuration

Introduction

Requirements

Project Structure

Maven Dependencies

Codes

Add Server

Server.java

TomcatServer.java

Add Launcher

SpringMVCGreetingsApplication.java

Add Configuration

ApplicationWebConfiguration.java

ApplicationInitializer.java

Add Controller

HomeController.java

GreetingsController.java

Add Static Assets

Add JSP templates

includes

head.jsp

header.jsp

footer.jsp

home

index.jsp

greetings

index.jsp

Build Application

Run Application

View Application in the browser

Screenshots

Home Page

Greetings Page

View Greetings Modal

Conclusion

Clone the source