How to Build & Deploy a HelloWorld API function using Java on OpenShift in 8 Steps

How to Build & Deploy a HelloWorld API function using Java on OpenShift in 8 Steps

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  How to build& deploy a HelloWorld API function using Java on OpenShift in 8 steps Jan Vosecky twitter: @jvosecky
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  In this tutorial •For OpenShift beginners • IDE: Eclipse – no command line used • Language: Java • Goal: build and deploy a HelloWorld API function
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  Step 1: InEclipse… • Install Eclipse plugin for OpenShift – Menu Help > Eclipse Marketplace – In the search box, type: jboss tools – Choose the plugin depending on your version of Eclipse
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  Step 2: OpenShift.com •https://www.openshift.com/ – Register account – Login to your account, where you can: • Create, manage, delete apps • Find Quickstarts and deploy them • Documentation: – https://www.openshift.com/developers
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  Step 3: InEclipse • Create a new OpenShift application – New > Project… > OpenShift > OpenShift Application • Login with your OpenShift account • Add your SSH keys – If you don’t have SSH keys, the wizard can generate them for you • Add 2 new windows in Eclipse: – Window > Show View > Other > 1. Git > Git staging 2. Jboss Tools > OpenShift Explorer
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  Structure of aJava web app Your Java code (*.java) Any other files needed by Java (config, txt, xml, etc) Frontend (html, css, jsp, etc)
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  Step 4: HelloWordAPI function package api; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.*; import javax.servlet.http.*; public class HelloWorld extends HttpServlet { private static final long serialVersionUID = -3950937333898038206L; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String name = request.getParameter("name"); PrintWriter out = response.getWriter(); out.println("{"status":"Hello " + name + "!""); out.flush(); out.close(); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } } Under folder: src/main/java/api/
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  Step 5: Adda dependency – Similar to “include a library” in a desktop Java application – Here we don’t include any JAR file, instead we point to a central repository that contains *most* libraries – Open pom.xml: • Tab: Dependencies • Seach for: javaee-web-api – Wanna add other dependencies? • Search for them: e.g., “mysql”
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  Step 6: Updateweb.xml <web-app version="3.0” xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" metadata-complete="false"> <servlet> <servlet-name>HelloWorld</servlet-name> <servlet-class>api.HelloWorld</servlet-class> </servlet> <servlet-mapping> <servlet-name>HelloWorld</servlet-name> <url-pattern>/api/HelloWorld</url-pattern> </servlet-mapping> </web-app> Under folder: src/main/webapp/WEB-INF/
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  Step 7: Commitand Push your code 1 2 3
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  Step 8: Seethe result! • Frontend: http://[APP NAME]-[YOUR DOMAIN].rhcloud.com • API: http://[APP NAME]-[YOUR DOMAIN].rhcloud.com/api/HelloWorld?name=Joe
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  Useful Links • Presentations: –http://www.slideshare.net/XavierCoulon/devoxx2013-fr- jbdsopenshift?qid=15557a00-3f56-4899-9572- dc03301e7bd6&v=default&b=&from_search=14 – http://www.slideshare.net/anoochit/using-openshift-paas?qid=15557a00-3f56- 4899-9572-dc03301e7bd6&v=default&b=&from_search=13 • Getting started: – https://www.openshift.com/get-started • Tutorial for Java & Eclipse: – https://www.openshift.com/blogs/day-28-openshift-eclipse-integration- for-java-developers • Lots of tutorials: – https://www.openshift.com/author/shekhar-gulati