Creating a Hello App Using Google App Engine

What are Google apps?

• Apps is an abbreviation for application. An app is a piece of software. It can run on the Internet, on your computer, or on your phone or other electronic device.• Google refers to their online services as apps, but

they also sell a specific suite of services known as Google Apps and have an application hosting service called Google Appengine.

What is google appengine?

•Google App Engine is a way to write your own Web applications and have them hosted on Google servers.

•Google Apps can be found on the Web at www.google.com/a

•And Google App Engine can be found on the Web at code.google.com/appengine.

Cont…

•You can serve your app using a free name on the appspot.com domain. You can share your application with the world, or limit access to members of your organization.

Registering the Application

1. App Engine Administration Console, at the following URL:

https://appengine.google.com/2. Sign in to App Engine using your Google account3. To create a new application:

a) Click the "Create an Application" buttonb) Follow the instructions to register an application ID,

a name unique to this applicationc)If you select to use the free appspot.com domain name,

the full URL for the application will be http://application-id.appspot.com/

Sign in to gmail account:

How to make Google app?

•To make google app we need following 1. eclipse 2. google plugin for eclipse

Eclipse

• Eclipse is a multi-language software development environment comprising an integrated development environment (IDE) and an extensible plugin system. It is written mostly in java and can be used to develop applications in Java and, by means of various plug-ins, other programming language including C, C++ etc.

How to download eclipse?

•Eclipse is an open source software .• Its different versions are easily available on internet .•http://www.eclipse.org/downloads/•To download eclipse first you have to install java run

time environment.

Installing eclipse:

•Go to the site:•http://www.poweredbypulse.com/

eclipse_packages_win.php•Select the eclipse version 3.6

Installing eclipse classic:

Step1:Check Google plugin for eclipse

Step2:click on install button

Installation started:

Plugin installed:

Creating web application project

Creating new web application project:

Project created:

The Project Directory • A single directory named

Project_Name/ for all project files.

• Subdirectory named src/ contains the Java source code

• Subdirectory named war/ contains the complete application arranged in the WAR format.

• Build process compiles the Java source files and puts the compiled classes in the appropriate location in war/

The servlet class:•App Engine Java applications use the Java Servlet

API to interact with the web server.• An HTTPservlet is an application class that can

process and respond to web requests.•Servlet class extends either the

javax.servlet.GenericServlet class or the javax.servlet.http.HttpServlet class.

Servlet class:

The web.xml File:

•When the web server receives a request, web.xml file is used to determines which servlet class to call

•web.xml resides in the war/WEB-INF/ directory •web.xml file declares a servlet named Yusra, and

maps it to the URL path /yusra•whenever the user fetches a URL path that is not

already mapped to a servlet, the server should check for a file named index.html in that directory and serve it if found.

Xml file:

The appengine-web.xml File

•This file is named appengine-web.xml, and resides in WEB-INF/ alongside web.xml

• It includes:▫The registered ID of your application (Eclipse creates

this with an empty ID for you to fill in later), ▫The version number of your application, ▫Lists of files:

Static files (such as images and CSS) and resource files (such as JSPs and other application data)

appengine-web.xml file:

Running the project:• The App Engine SDK includes a web server

application you can use to test your application • Steps:

▫ Make sure the project (“Yusra") is selected, ▫ Right click and select Run As menu▫ Select Web Application

• This should start Jetty on http://localhost:8888/

Testing the Application:

Deploying Application:

• Now deploy your application to the Google cloud• You must have a google mail account• Give application ID to you application– Application ID will be stored in file (“appengine-

web.xml”• First you will have to register application on google

cloud–Using the same application ID

• Then perform deploying operation

Uploading From Eclipse• To upload your application from Eclipse, click the

App Engine deploy button on the toolbar

• Click the Deploy button

• Enter your Google account username (your email address) and password when prompted

• Eclipse gets the application ID and version information from the appengine-web.xml file, and uploads the contents of the war/ directory.

Deploying project:

Click on deploy button:

Deployment started:

Accessing Your Application

•You can now see your application running on App Engine

• If you set up a free appspot.com domain name, the URL for your website begins with your application ID:

http://application-id.appspot.com/• In our example it will be http://hiyzfriends.appspot.com/yusra

Uploaded successfully: