Chapter 3. Developing and deploying a Spring Boot runtime application

Procedure

1. Create a new directory myApp, and navigate to it.

   $ mkdir myApp
   $ cd myApp

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   This is the root directory for the application.

2. Create directory structure src/main/java/com/example/ in the root directory, and navigate to it.

   $ mkdir -p src/main/java/com/example/
   $ cd src/main/java/com/example/

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3. Create a Java class file MyApp.java containing the application code.

   package com.example;
   
   import org.springframework.boot.SpringApplication;
   import org.springframework.boot.autoconfigure.SpringBootApplication;
   import org.springframework.web.bind.annotation.RequestMapping;
   import org.springframework.web.bind.annotation.ResponseBody;
   import org.springframework.web.bind.annotation.RestController;
   
   @SpringBootApplication
   @RestController
   public class MyApp {
   
       public static void main(String[] args) {
           SpringApplication.run(MyApp.class, args);
       }
   
       @RequestMapping("/")
       @ResponseBody
       public Message displayMessage() {
           return new Message();
       }
   
       static class Message {
           private String content = "Greetings!";
   
           public String getContent() {
               return content;
           }
   
           public void setContent(String content) {
               this.content = content;
           }
       }
   }

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4. Create a pom.xml file in the application root directory myApp with the following content:

   <?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>
   
     <groupId>com.example</groupId>
     <artifactId>my-app</artifactId>
     <version>1.0.0-SNAPSHOT</version>
   
     <name>MyApp</name>
     <description>My Application</description>
   
     <!-- Import dependencies from the Spring Boot BOM. -->
     <dependencyManagement>
       <dependencies>
         <dependency>
           <groupId>dev.snowdrop</groupId>
           <artifactId>snowdrop-dependencies</artifactId>
           <version>2.4.9.Final-redhat-00001</version>
           <type>pom</type>
           <scope>import</scope>
         </dependency>
         <dependency>
           <groupId>io.dekorate</groupId>
           <artifactId>openshift-spring-starter</artifactId>
         </dependency>
         <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-tomcat</artifactId>
         </dependency>
         <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-actuator</artifactId>
         </dependency>
         <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
       </dependencies>
     </dependencyManagement>
   
     <build>
       <plugins>
         <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
           <version>2.4.9</version>
         </plugin>
       </plugins>
     </build>
   
     <!-- Specify the repositories containing Spring Boot artifacts -->
     <repositories>
       <repository>
         <id>redhat-ga</id>
         <name>Red Hat GA Repository</name>
         <url>https://maven.repository.redhat.com/ga/</url>
       </repository>
     </repositories>
   
     <pluginRepositories>
       <pluginRepository>
         <id>redhat-ga</id>
         <name>Red Hat GA Repository</name>
         <url>https://maven.repository.redhat.com/ga/</url>
       </pluginRepository>
     </pluginRepositories>
   
   </project>

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5. Build the application using Maven from the root directory of the application.

   $ mvn clean package -Popenshift -Ddekorate.deploy=true

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6. Verify that the application is running.

   Using curl or your browser, verify your application is running at http://localhost:8080.

   $ curl http://localhost:8080
   {"content":"Greetings!"}

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