Spring Boot Hello World Example Mustache

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

Technologies used :

1. Spring Boot 1.5.2.RELEASE
2. Spring 4.3.7.RELEASE
3. jmustache 1.13
4. Thymeleaf 2.1.5.RELEASE
5. Tomcat Embed 8.5.11
6. Maven 3
7. Java 8

1. Project Directory

2. Project Dependencies

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

<?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-mustache</artifactId>
	<packaging>jar</packaging>
	<name>Spring Boot Web Mustache Example</name>
	<description>Spring Boot Web Mustache 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>1.5.2.RELEASE</version>
	</parent>
	<properties>
		<java.version>1.8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-mustache</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<!-- hot swapping, 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 Mustache Example 1.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-dependency-plugin:2.10:tree (default-cli) @ spring-boot-web-mustache ---
                               [INFO] org.springframework.boot:spring-boot-web-mustache:jar:1.0
[INFO] +- org.springframework.boot:spring-boot-starter-mustache:jar:1.5.2.RELEASE:compile
[INFO] |  +- org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-starter-logging:jar:1.5.2.RELEASE:compile
[INFO] |  |  |  +- ch.qos.logback:logback-classic:jar:1.1.11:compile
[INFO] |  |  |  |  \- ch.qos.logback:logback-core:jar:1.1.11:compile
[INFO] |  |  |  +- org.slf4j:jcl-over-slf4j:jar:1.7.24:compile
[INFO] |  |  |  +- org.slf4j:jul-to-slf4j:jar:1.7.24:compile
[INFO] |  |  |  \- org.slf4j:log4j-over-slf4j:jar:1.7.24:compile
[INFO] |  |  \- org.yaml:snakeyaml:jar:1.17:runtime
[INFO] |  +- org.springframework.boot:spring-boot-starter-web:jar:1.5.2.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-starter-tomcat:jar:1.5.2.RELEASE:compile
[INFO] |  |  |  +- org.apache.tomcat.embed:tomcat-embed-core:jar:8.5.11:compile
[INFO] |  |  |  +- org.apache.tomcat.embed:tomcat-embed-el:jar:8.5.11:compile
[INFO] |  |  |  \- org.apache.tomcat.embed:tomcat-embed-websocket:jar:8.5.11:compile
[INFO] |  |  +- org.hibernate:hibernate-validator:jar:5.3.4.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:2.8.7:compile
[INFO] |  |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile
[INFO] |  |  |  \- com.fasterxml.jackson.core:jackson-core:jar:2.8.7:compile
[INFO] |  |  +- org.springframework:spring-web:jar:4.3.7.RELEASE:compile
[INFO] |  |  |  +- org.springframework:spring-aop:jar:4.3.7.RELEASE:compile
[INFO] |  |  |  \- org.springframework:spring-beans:jar:4.3.7.RELEASE:compile
[INFO] |  |  \- org.springframework:spring-webmvc:jar:4.3.7.RELEASE:compile
[INFO] |  |     \- org.springframework:spring-expression:jar:4.3.7.RELEASE:compile
[INFO] |  \- com.samskivert:jmustache:jar:1.13:compile
[INFO] +- org.springframework.boot:spring-boot-starter-test:jar:1.5.2.RELEASE:test
[INFO] |  +- org.springframework.boot:spring-boot-test:jar:1.5.2.RELEASE:test
[INFO] |  +- org.springframework.boot:spring-boot-test-autoconfigure:jar:1.5.2.RELEASE:test
[INFO] |  +- com.jayway.jsonpath:json-path:jar:2.2.0:test
[INFO] |  |  +- net.minidev:json-smart:jar:2.2.1:test
[INFO] |  |  |  \- net.minidev:accessors-smart:jar:1.1:test
[INFO] |  |  |     \- org.ow2.asm:asm:jar:5.0.3:test
[INFO] |  |  \- org.slf4j:slf4j-api:jar:1.7.24:compile
[INFO] |  +- junit:junit:jar:4.12:test
[INFO] |  +- org.assertj:assertj-core:jar:2.6.0:test
[INFO] |  +- org.mockito:mockito-core:jar:1.10.19:test
[INFO] |  |  \- org.objenesis:objenesis:jar:2.1:test
[INFO] |  +- org.hamcrest:hamcrest-core:jar:1.3:test
[INFO] |  +- org.hamcrest:hamcrest-library:jar:1.3:test
[INFO] |  +- org.skyscreamer:jsonassert:jar:1.4.0:test
[INFO] |  |  \- com.vaadin.external.google:android-json:jar:0.0.20131108.vaadin1:test
[INFO] |  +- org.springframework:spring-core:jar:4.3.7.RELEASE:compile
[INFO] |  \- org.springframework:spring-test:jar:4.3.7.RELEASE:test
[INFO] +- org.springframework.boot:spring-boot-devtools:jar:1.5.2.RELEASE:compile
[INFO] |  +- org.springframework.boot:spring-boot:jar:1.5.2.RELEASE:compile
[INFO] |  |  \- org.springframework:spring-context:jar:4.3.7.RELEASE:compile
[INFO] |  \- org.springframework.boot:spring-boot-autoconfigure:jar:1.5.2.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: 1.796 s
[INFO] Finished at: 2017-04-19T11:46:09+08:00
[INFO] Final Memory: 22M/437M
[INFO] ------------------------------------------------------------------------

3. Spring Boot

3.1 Create a @SpringBootApplication class. Run this class to start the Spring Boot web application.

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 controller class.

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("${app.welcome.message}")
	private String MESSAGE = "";
	@Value("${app.welcome.title}")
	private String TITLE = "";
	@RequestMapping("/")
	public String welcome(Map<String, Object> model) {
		model.put("title", TITLE);
		model.put("message", MESSAGE);
		return "welcome";
	// test 5xx errors
	@RequestMapping("/5xx")
	public String ServiceUnavailable() {
		throw new RuntimeException("ABC");

4. Mustache + Resources + Static files

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

<!DOCTYPE HTML>
<head>
<title>{{title}}</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" href="css/main.css" />
</head>
<!--  this is header -->

<!--  this is footer -->
</html>

{{>layout/header}}
<body>
	<nav class="navbar navbar-inverse">
		<div class="container">
			<div class="navbar-header">
				<a class="navbar-brand" href="#">Spring Boot</a>
			</div>
		</div>
	</nav>
	<div class="container">
		<div class="starter-template">
			<h1>Spring Boot Web Mustache Example</h1>
			<h2>
				{{message}}
			</h2>
		</div>
	</div>
	<!-- /.container -->
	<script type="text/javascript" src="webjars/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</body>
{{>layout/footer}}

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

h1{
	color:#0000FF;
h2{
	color:#FF0000;

4.3 For error templates.

<!DOCTYPE html>
<html lang="en">
<body>
	Something went wrong: {{status}} {{error}}
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<body>
	I'm a 5xx
</body>
</html>

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

app.welcome.message: Hello Mkyong
app.welcome.title: Spring Boot Mustache Hello World Example

5. Unit Test

5.1 Unit test example to test above Spring Boot web application.

package com.mkyong;
import static org.assertj.core.api.Assertions.assertThat;
import java.util.Arrays;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.test.annotation.DirtiesContext;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
@DirtiesContext
public class MustacheApplicationTests {
	@Autowired
	private TestRestTemplate restTemplate;
	@Test
	public void testMainPage() throws Exception {
		ResponseEntity<String> entity = this.restTemplate.getForEntity("/", String.class);
		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
		assertThat(entity.getBody()).contains("Hello Mkyong");
	@Test
	public void test404Page() throws Exception {
		HttpHeaders headers = new HttpHeaders();
		headers.setAccept(Arrays.asList(MediaType.TEXT_HTML));
		HttpEntity<String> requestEntity = new HttpEntity<String>(headers);
		ResponseEntity<String> responseEntity = this.restTemplate.exchange("/uri-not-exist", HttpMethod.GET,
				requestEntity, String.class);
		assertThat(responseEntity.getStatusCode()).isEqualTo(HttpStatus.NOT_FOUND);
		assertThat(responseEntity.getBody()).contains("Something went wrong: 404 Not Found");
	@Test
	public void test5xxPage() throws Exception {
		HttpHeaders headers = new HttpHeaders();
		headers.setAccept(Arrays.asList(MediaType.TEXT_HTML));
		HttpEntity<String> requestEntity = new HttpEntity<String>(headers);
		ResponseEntity<String> responseEntity = this.restTemplate.exchange("/5xx", HttpMethod.GET, requestEntity,
				String.class);
		assertThat(responseEntity.getStatusCode()).isEqualTo(HttpStatus.INTERNAL_SERVER_ERROR);
		assertThat(responseEntity.getBody()).contains("I'm a 5xx");

6. Demo

6.1 Start the Spring Boot web app.

project$ mvn spring-boot:run
//...
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.2.RELEASE)
2017-04-19 12:17:38.014  INFO 6232 --- [  restartedMain] com.mkyong.SpringBootWebApplication      : Starting SpringBootWebApplication on MKYONG-WIN10 with PID 6232 (C:\spring-boot\spring-boot-examples\spring-boot-web-mustache\target\classes started by mkyong in C:\spring-boot\spring-boot-examples\spring-boot-web-mustache)
2017-04-19 12:17:38.015  INFO 6232 --- [  restartedMain] com.mkyong.SpringBootWebApplication      : No active profile set, falling back to default profiles: default
2017-04-19 12:17:38.074  INFO 6232 --- [  restartedMain] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@af1619: startup date [Wed Apr 19 12:17:38 SGT 2017]; root of context hierarchy
2017-04-19 12:17:39.352  INFO 6232 --- [  restartedMain] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-04-19 12:17:39.370  INFO 6232 --- [  restartedMain] o.apache.catalina.core.StandardService   : Starting service Tomcat
2017-04-19 12:17:39.372  INFO 6232 --- [  restartedMain] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.11
2017-04-19 12:17:39.481  INFO 6232 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2017-04-19 12:17:39.481  INFO 6232 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1410 ms
2017-04-19 12:17:39.649  INFO 6232 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2017-04-19 12:17:39.658  INFO 6232 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-04-19 12:17:39.659  INFO 6232 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-04-19 12:17:39.659  INFO 6232 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-04-19 12:17:39.660  INFO 6232 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2017-04-19 12:17:39.938  INFO 6232 --- [  restartedMain] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@af1619: startup date [Wed Apr 19 12:17:38 SGT 2017]; root of context hierarchy
2017-04-19 12:17:39.997  INFO 6232 --- [  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>)
2017-04-19 12:17:39.997  INFO 6232 --- [  restartedMain] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/5xx]}" onto public java.lang.String com.mkyong.WelcomeController.ServiceUnavailable()
2017-04-19 12:17:40.006  INFO 6232 --- [  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)
2017-04-19 12:17:40.006  INFO 6232 --- [  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)
2017-04-19 12:17:40.041  INFO 6232 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-19 12:17:40.041  INFO 6232 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-19 12:17:40.090  INFO 6232 --- [  restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-04-19 12:17:40.332  INFO 6232 --- [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2017-04-19 12:17:40.373  INFO 6232 --- [  restartedMain] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-04-19 12:17:40.427  INFO 6232 --- [  restartedMain] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-04-19 12:17:40.435  INFO 6232 --- [  restartedMain] com.mkyong.SpringBootWebApplication      : Started SpringBootWebApplication in 2.737 seconds (JVM running for 3.124)

6.2 Access http://localhost:8080

6.2 Access http://localhost:8080/uri-not-exist

6.2 Access http://localhost:8080/5xx

6. Build an executable JAR

6.1 Package the project to create an executable JAR file.

project$ mvn clean package

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

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

References

1. Mustache template engine
2. jmustache – A Java implementation of the Mustache templating language
3. Spring Boot – Error Handling
4. Spring Boot – Static content
5. Deploying Spring Boot Applications
6. Spring MVC – Inlucde CSS file
7. Spring Boot – Developer tools
8. Serving Web Content with Spring MVC
9. Spring Boot Hello World Example – JSP