A Spring Boot web application example, using embedded Tomcat + Thymeleaf template engine, and package as an executable JAR file.

Technologies used :

  1. Spring Boot 1.4.2.RELEASE
  2. Spring 4.3.4.RELEASE
  3. Thymeleaf 2.1.5.RELEASE
  4. Tomcat Embed 8.5.6
  5. Maven 3
  6. Java 8

1. Project Directory

Create the following folders manually :

spring-boot-thymeleaf-hello-world-example

2. Project Dependencies

Declares spring-boot-starter-thymeleaf, it will get anything you need to develop a Spring + Thymeleaf web application.

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>

	<artifactId>spring-boot-web-thymeleaf</artifactId>
	<packaging>jar</packaging>
	<name>Spring Boot Web Thymeleaf Example</name>
	<description>Spring Boot Web Thymeleaf Example</description>
	<url>https://www.mkyong.com</url>
	<version>1.0</version>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.4.2.RELEASE</version>
	</parent>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</artifactId>
		</dependency>

		<!-- hot swapping, disable cache for template, enable live reload -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<optional>true</optional>
		</dependency>

		<!-- Optional, for bootstrap -->
		<dependency>
			<groupId>org.webjars</groupId>
			<artifactId>bootstrap</artifactId>
			<version>3.3.7</version>
		</dependency>

	</dependencies>
	
	<build>
		<plugins>
			<!-- Package as an executable jar/war -->
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

Display project dependencies :


$ mvn dependency:tree

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Spring Boot Web Thymeleaf Example 1.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-dependency-plugin:2.10:tree (default-cli) @ spring-boot-web-thymeleaf ---
[INFO] org.springframework.boot:spring-boot-web-thymeleaf:jar:1.0
[INFO] +- org.springframework.boot:spring-boot-starter-thymeleaf:jar:1.4.2.RELEASE:compile
[INFO] |  +- org.springframework.boot:spring-boot-starter:jar:1.4.2.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-starter-logging:jar:1.4.2.RELEASE:compile
[INFO] |  |  |  +- ch.qos.logback:logback-classic:jar:1.1.7:compile
[INFO] |  |  |  |  \- ch.qos.logback:logback-core:jar:1.1.7:compile
[INFO] |  |  |  +- org.slf4j:jcl-over-slf4j:jar:1.7.21:compile
[INFO] |  |  |  +- org.slf4j:jul-to-slf4j:jar:1.7.21:compile
[INFO] |  |  |  \- org.slf4j:log4j-over-slf4j:jar:1.7.21:compile
[INFO] |  |  +- org.springframework:spring-core:jar:4.3.4.RELEASE:compile
[INFO] |  |  \- org.yaml:snakeyaml:jar:1.17:runtime
[INFO] |  +- org.springframework.boot:spring-boot-starter-web:jar:1.4.2.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-starter-tomcat:jar:1.4.2.RELEASE:compile
[INFO] |  |  |  +- org.apache.tomcat.embed:tomcat-embed-core:jar:8.5.6:compile
[INFO] |  |  |  +- org.apache.tomcat.embed:tomcat-embed-el:jar:8.5.6:compile
[INFO] |  |  |  \- org.apache.tomcat.embed:tomcat-embed-websocket:jar:8.5.6:compile
[INFO] |  |  +- org.hibernate:hibernate-validator:jar:5.2.4.Final:compile
[INFO] |  |  |  +- javax.validation:validation-api:jar:1.1.0.Final:compile
[INFO] |  |  |  +- org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile
[INFO] |  |  |  \- com.fasterxml:classmate:jar:1.3.3:compile
[INFO] |  |  +- com.fasterxml.jackson.core:jackson-databind:jar:2.8.4:compile
[INFO] |  |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.8.4:compile
[INFO] |  |  |  \- com.fasterxml.jackson.core:jackson-core:jar:2.8.4:compile
[INFO] |  |  +- org.springframework:spring-web:jar:4.3.4.RELEASE:compile
[INFO] |  |  |  +- org.springframework:spring-aop:jar:4.3.4.RELEASE:compile
[INFO] |  |  |  \- org.springframework:spring-beans:jar:4.3.4.RELEASE:compile
[INFO] |  |  \- org.springframework:spring-webmvc:jar:4.3.4.RELEASE:compile
[INFO] |  |     \- org.springframework:spring-expression:jar:4.3.4.RELEASE:compile
[INFO] |  +- org.thymeleaf:thymeleaf-spring4:jar:2.1.5.RELEASE:compile
[INFO] |  |  +- org.thymeleaf:thymeleaf:jar:2.1.5.RELEASE:compile
[INFO] |  |  |  +- ognl:ognl:jar:3.0.8:compile
[INFO] |  |  |  +- org.javassist:javassist:jar:3.20.0-GA:compile
[INFO] |  |  |  \- org.unbescape:unbescape:jar:1.1.0.RELEASE:compile
[INFO] |  |  \- org.slf4j:slf4j-api:jar:1.7.21:compile
[INFO] |  \- nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect:jar:1.4.0:compile
[INFO] |     \- org.codehaus.groovy:groovy:jar:2.4.7:compile
[INFO] +- org.springframework.boot:spring-boot-devtools:jar:1.4.2.RELEASE:compile
[INFO] |  +- org.springframework.boot:spring-boot:jar:1.4.2.RELEASE:compile
[INFO] |  |  \- org.springframework:spring-context:jar:4.3.4.RELEASE:compile
[INFO] |  \- org.springframework.boot:spring-boot-autoconfigure:jar:1.4.2.RELEASE:compile
[INFO] \- org.webjars:bootstrap:jar:3.3.7:compile
[INFO]    \- org.webjars:jquery:jar:1.11.1:compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.429 s
[INFO] Finished at: 2016-12-03T13:25:06+08:00
[INFO] Final Memory: 20M/309M
[INFO] ------------------------------------------------------------------------
spring-boot-devtools

This spring-boot-devtools helps to disable the caches and enable hot swapping so that developers will always see the last changes. Good for development. Read this – Spring Boot – Developer tools.

Try to modify the Thymeleaf templates or properties files, refresh the browser to see the changes take effect immediately.

3. Spring Boot

3.1 Annotate with @SpringBootApplication, that’s all. Run this class to start the Spring Boot web application.

SpringBootWebApplication.java

package com.mkyong;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootWebApplication {

	public static void main(String[] args) throws Exception {
		SpringApplication.run(SpringBootWebApplication.class, args);
	}

}

3.2 A simple Spring controller class.

WelcomeController.java

package com.mkyong;

import java.util.Map;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class WelcomeController {

	// inject via application.properties
	@Value("${welcome.message:test}")
	private String message = "Hello World";

	@RequestMapping("/")
	public String welcome(Map<String, Object> model) {
		model.put("message", this.message);
		return "welcome";
	}

}

4. Thymeleaf + Resources + Static files

4.1 For Thymeleaf template files, put in src/main/resources/templates/

src/main/resources/templates/welcome.html

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>Spring Boot Thymeleaf Hello World Example</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

<link rel="stylesheet" type="text/css"
	href="webjars/bootstrap/3.3.7/css/bootstrap.min.css" />

<link rel="stylesheet" th:href="@{/css/main.css}"
	href="../../css/main.css" />

</head>
<body>

	<nav class="navbar navbar-inverse">
		<div class="container">
			<div class="navbar-header">
				<a class="navbar-brand" href="#">Spring Boot</a>
			</div>
			<div id="navbar" class="collapse navbar-collapse">
				<ul class="nav navbar-nav">
					<li class="active"><a href="#">Home</a></li>
					<li><a href="#about">About</a></li>
				</ul>
			</div>
		</div>
	</nav>

	<div class="container">

		<div class="starter-template">
			<h1>Spring Boot Web Thymeleaf Example</h1>
			<h2>
				<span th:text="'Message: ' + ${message}"></span>
			</h2>
		</div>

	</div>
	<!-- /.container -->

	<script type="text/javascript"
		src="webjars/bootstrap/3.3.7/js/bootstrap.min.js"></script>

</body>
</html>

4.2 For static files like CSS or Javascript, put in /src/main/resources/static/

/src/main/resources/static/css/main.css

h1{
	color:#0000FF;
}

h2{
	color:#FF0000;
}

4.3 For properties files, put in /src/main/resources/

/src/main/resources/application.properties

welcome.message: Hello Mkyong
Note
Read this Spring Boot Serving static content to understand the resource mapping.

5. Demo

5.1 Start the Spring Boot web app.


project$ mvn spring-boot:run

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.4.2.RELEASE)

2016-12-03 14:04:07.203  INFO 7180 --- [  restartedMain] com.mkyong.SpringBootWebApplication      : Starting SpringBootWebApplication on MKYONG-WIN10 with PID 7180 (C:\spring-boot\spring-boot-examples\spring-boot-web-thymeleaf\target\classes started by mkyong in C:\spring-boot\spring-boot-examples\spring-boot-web-thymeleaf)
2016-12-03 14:04:07.205  INFO 7180 --- [  restartedMain] com.mkyong.SpringBootWebApplication      : No active profile set, falling back to default profiles: default
2016-12-03 14:04:07.392  INFO 7180 --- [  restartedMain] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@67af925a: startup date [Sat Dec 03 14:04:07 SGT 2016]; root of context hierarchy
2016-12-03 14:04:08.739  INFO 7180 --- [  restartedMain] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2016-12-03 14:04:08.754  INFO 7180 --- [  restartedMain] o.apache.catalina.core.StandardService   : Starting service Tomcat
2016-12-03 14:04:08.755  INFO 7180 --- [  restartedMain] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.6
2016-12-03 14:04:08.827  INFO 7180 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2016-12-03 14:04:08.827  INFO 7180 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1439 ms
2016-12-03 14:04:08.969  INFO 7180 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2016-12-03 14:04:08.976  INFO 7180 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2016-12-03 14:04:08.977  INFO 7180 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2016-12-03 14:04:08.978  INFO 7180 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2016-12-03 14:04:08.980  INFO 7180 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2016-12-03 14:04:09.196  INFO 7180 --- [  restartedMain] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@67af925a: startup date [Sat Dec 03 14:04:07 SGT 2016]; root of context hierarchy
2016-12-03 14:04:09.242  INFO 7180 --- [  restartedMain] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto public java.lang.String com.mkyong.WelcomeController.welcome(java.util.Map<java.lang.String, java.lang.Object>)
2016-12-03 14:04:09.247  INFO 7180 --- [  restartedMain] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2016-12-03 14:04:09.247  INFO 7180 --- [  restartedMain] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2016-12-03 14:04:09.277  INFO 7180 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-12-03 14:04:09.277  INFO 7180 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-12-03 14:04:09.319  INFO 7180 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-12-03 14:04:09.687  INFO 7180 --- [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2016-12-03 14:04:09.724  INFO 7180 --- [  restartedMain] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-12-03 14:04:09.781  INFO 7180 --- [  restartedMain] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2016-12-03 14:04:09.787  INFO 7180 --- [  restartedMain] com.mkyong.SpringBootWebApplication      : Started SpringBootWebApplication in 2.943 seconds (JVM running for 3.325)

5.2 Access http://localhost:8080

spring-boot-thymeleaf-hello-world-example-output

6. Build an executable JAR

6.1 Package the project to create an executable JAR file.


project$ mvn clean package

...
[INFO] ------------------------------------------------------------------------
[INFO] Building Spring Boot Web Thymeleaf Example 1.0
[INFO] ------------------------------------------------------------------------
...
[INFO] --- maven-jar-plugin:2.6:jar (default-jar) @ spring-boot-web-thymeleaf ---
[INFO] Building jar: C:\spring-boot\spring-boot-examples\spring-boot-web-thymeleaf\target\spring-boot-web-thymeleaf-1.0.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:1.4.2.RELEASE:repackage (default) @ spring-boot-web-thymeleaf ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.797 s
[INFO] Finished at: 2016-12-03T14:06:45+08:00
[INFO] Final Memory: 21M/437M
[INFO] ------------------------------------------------------------------------

6.2 Run It, access http://localhost:8080 again.


project$ java -jar target/spring-boot-web-thymeleaf-1.0.jar

Download Source Code

Download it – spring-boot-web-thymeleaf.zip (9 KB)

References

  1. Thymeleaf official website
  2. Spring Boot – Static content
  3. Deploying Spring Boot Applications
  4. Spring MVC – Inlucde CSS file
  5. Spring Boot – Developer tools
  6. Serving Web Content with Spring MVC
  7. Spring Boot Hello World Example – JSP