# [Optional] Spring Framework Lab

Review all the necessary steps required to create a simple web application with the Spring Framework 5.

Time: 25 minutes.

## Requirements:

- Java 1.8 (recommended)

- Maven 3.x installed.

- Tomcat 8.5.x installed.

## Simple Spring Web Application with Thymeleaf

1. To create a simple Spring Web application, open a terminal window and execute the following statement:

       mvn archetype:generate -DgroupId=io.pivotal.workshop -DartifactId=simple-spring-webapp -Dversion=1.0-SNAPSHOT -DinteractiveMode=false -DarchetypeArtifactId=maven-archetype-webapp

   | If you have a Maven version below 3.x, you need to use the command mvn archetype:create instead.

2. Create the missing Java EE structure (ex: src/main/java, src/main/webapp/WEB-INF, etc.)

3. Create the web controller SimpleController class in src/main/java/io/pivotal/workshop/web folder.

   io.pivotal.workshop.web.SimpleController.java

       package io.pivotal.workshop.web;

       import org.slf4j.Logger;
       import org.slf4j.LoggerFactory;
       import org.springframework.stereotype.Controller;
       import org.springframework.web.bind.annotation.RequestMapping;
       import org.springframework.web.bind.annotation.RequestMethod;
       import org.springframework.web.servlet.ModelAndView;

       @Controller
       public class SimpleController{

               Logger log = LoggerFactory.getLogger(SimpleController.class);

               @RequestMapping("/")
               public ModelAndView index(){
                       log.debug("About to redirect...");
                       return new ModelAndView("redirect:/showMessage");
               }

               @RequestMapping(value="/showMessage",method = RequestMethod.GET)
               public ModelAndView helloWorld(){
                       final String message = "Simple Spring MVC Web App with Thymeleaf and Spring 5";
                        log.debug("Showing the Message: " + message);
                       ModelAndView model = new ModelAndView("showMessage");
                       model.addObject("message", message);
                       return model;
               }
       }

4. Modify the src/main/webapp/WEB-INF/web.xml file.

   web.xml

       <!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd" >

       <web-app>
         <display-name>Simple Spring Web Application</display-name>

         <servlet>
             <servlet-name>dispatcherServlet</servlet-name>
             <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
             <load-on-startup>1</load-on-startup>
         </servlet>

         <servlet-mapping>
             <servlet-name>dispatcherServlet</servlet-name>
             <url-pattern>/</url-pattern>
         </servlet-mapping>

       </web-app>

5. Create the src/main/webapp/WEB-INF/dispatcherServlet-servlet.xml file.

   dispatcherServlet-servlet.xml

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

       <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context"
               xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
                       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

               <!--
               DispatcherServlet creates its own WebApplicationContext and the handlers/controllers/view-resolvers are managed
               by this context.
               -->

                <context:component-scan base-package="io.pivotal.workshop.web" />

               <!-- Useful when only JSP is required. The javax.servlet.jsp:avax.servlet.jsp-api:2.3.1 dendency is necessary-->
               <!--
               <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
                       <property name="prefix" value="/WEB-INF/view/"/>
                       <property name="suffix" value=".jsp"/>
               </bean>
               -->

               <!-- Thymeleaf Configuration -->
               <bean id="templateResolver" class="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver">
                       <property name="prefix" value="/WEB-INF/view/" />
                       <property name="suffix" value=".html" />
                       <property name="templateMode" value="HTML5" />
               </bean>

               <bean id="templateEngine" class="org.thymeleaf.spring5.SpringTemplateEngine">
                       <property name="templateResolver" ref="templateResolver" />
                       <property name="enableSpringELCompiler" value="true" />
               </bean>

               <bean id="viewResolver" class="org.thymeleaf.spring5.view.ThymeleafViewResolver">
                       <property name="templateEngine" ref="templateEngine" />
       </bean>

       </beans>

6. Modify the src/main/webapp/index.html file and move it to the src/main/webapp/WEB-INF/view directory.

   index.html

       <!DOCTYPE html>

       <html lang="en" xmlns:th="http://www.thymeleaf.org">
               <head>
                       <meta charset="utf-8">
                       <title>Welcome</title>
               </head>
               <body>
                       <p>This page never will show up</p>
               </body>
       </html>

   This page will never show up, because the handler will do a redirect to the showMessage.html.

7. Create the src/main/webapp/WEB-INF/view/showMessage.html file.

   showMessage.jsp

       <!DOCTYPE html>

       <html lang="en" xmlns:th="http://www.thymeleaf.org">
               <head>
                       <meta charset="utf-8">
                       <title>Welcome</title>
               </head>
               <body style="font-family: Verdana, sans-serif;">
               <h2><p th:text="${message}"/></h2>
               </body>
       </html>

8. Create the logging configuration. Create a logback.xml file in the src/main/resources directory.

   logback.xml

       <configuration>
           <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
               <encoder>
                   <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
               </encoder>
           </appender>

           <logger name="io.pivotal.workshop" level="DEBUG"/>
               <logger name="org.thymeleaf" level="OFF"/>

           <root level="INFO">
               <appender-ref ref="STDOUT" />
           </root>
       </configuration>

9. Modify the pom.xml file. Add the necessary dependencies. See all the Spring 5 dependencies.

   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/maven-v4_0_0.xsd">
               <modelVersion>4.0.0</modelVersion>
               <groupId>io.pivotal.workshop</groupId>
               <artifactId>simple-spring-webapp</artifactId>
               <packaging>war</packaging>
               <version>1.0-SNAPSHOT</version>
               <name>simple-spring-webapp Maven Webapp</name>
               <url>http://maven.apache.org</url>
               <parent>
                       <groupId>io.pivotal.education.boot</groupId>
                       <artifactId>parentProject</artifactId>
                       <version>1.0.a.RELEASE</version>
                       <relativePath>../../</relativePath>
               </parent>
               <properties>

                       <!-- Generic properties -->
                       <java.version>1.8</java.version>

                       <!-- Web -->
                       <servlet.version>3.1.0</servlet.version>

                       <!-- Spring -->
                       <spring-framework.version>5.0.1.RELEASE</spring-framework.version>

                       <!-- Thymeleaf -->
                       <thymeleaf.version>3.0.9.RELEASE</thymeleaf.version>

                       <!--  Logging -->
                       <slf4j.version>1.7.25</slf4j.version>
                       <logback.version>1.2.3</logback.version>
               </properties>

               <dependencies>

                       <!-- Spring MVC -->
                       <dependency>
                               <groupId>org.springframework</groupId>
                               <artifactId>spring-context</artifactId>
                               <version>${spring-framework.version}</version>
                       </dependency>
                       <dependency>
                               <groupId>org.springframework</groupId>
                               <artifactId>spring-aop</artifactId>
                               <version>${spring-framework.version}</version>
                       </dependency>
                       <dependency>
                               <groupId>org.springframework</groupId>
                               <artifactId>spring-webmvc</artifactId>
                               <version>${spring-framework.version}</version>
                       </dependency>
                       <dependency>
                               <groupId>org.springframework</groupId>
                               <artifactId>spring-web</artifactId>
                               <version>${spring-framework.version}</version>
                       </dependency>

                       <dependency>
                               <groupId>org.thymeleaf</groupId>
                               <artifactId>thymeleaf</artifactId>
                               <version>${thymeleaf.version}</version>
                       </dependency>
                       <dependency>
                               <groupId>org.thymeleaf</groupId>
                               <artifactId>thymeleaf-spring5</artifactId>
                               <version>${thymeleaf.version}</version>
                       </dependency>

                       <dependency>
                               <groupId>org.slf4j</groupId>
                               <artifactId>slf4j-api</artifactId>
                               <version>${slf4j.version}</version>
                       </dependency>
                       <dependency>
                               <groupId>ch.qos.logback</groupId>
                               <artifactId>logback-classic</artifactId>
                               <version>${logback.version}</version>
                       </dependency>

                       <!-- Other Web dependencies -->
                       <dependency>
                               <groupId>javax.servlet</groupId>
                               <artifactId>javax.servlet-api</artifactId>
                               <version>${servlet.version}</version>
                               <scope>provided</scope>
                       </dependency>
               </dependencies>

               <build>
                       <finalName>simple-spring-webapp</finalName>
               </build>
       </project>

### Building the Spring Web Application

To build the Spring Web application, execute the following command:

    mvn clean compile package

the above command will generate the target/simple-spring-webapp.war.

### Deploying the Spring Web Application

To deploy the application, install any application container that supports the Java Servlets specification.

For example, to deploy to Apache Tomcat, copy the target/simple-spring-webapp.war file into the $TOMCAT-INSTALLATION/webapps/ directory and start the container. Then, go to your browser and hit the http://localhost:8080/simple-spring-webapp/ URL.

You should see the text: Simple Spring MVC Web App with Thymeleaf and Spring 5.