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Developing and deploying a basic Java application on SAP Cloud Platform

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Developing and deploying a basic Java application on SAP Cloud Platform

By Jim Jaquet

Develop and deploy your first Java application using the SAP Cloud Platform Tools for Java

You will learn

In this tutorial you will create a Dynamic Web project, a servlet to respond to a browser request and after running it in your local development environment, deploy it to SAP Cloud Platform.

Details


Step 1: Open your Eclipse IDE

The first step in building your application is to create a new Dynamic Web Project. Open your Eclipse IDE with the installed SAP Cloud Platform Tools. Make sure the Java EE perspective is open by choosing Window > Open Perspective > Other.

open other perspective
Step 2: Choose Java EE (Default)

Then choose the perspective Java EE (Default) and confirm by clicking OK.

open J2EE perspective

The J2EE perspective is now open.

J2EE perspective is open
Step 3: Open Dynamic Web Project

In the Eclipse main menu choose File > New > Dynamic Web Project to open the respective wizard.

open wizard
Step 4: Set project name

In the New Dynamic Web Project Wizard define the Project name to be helloworld. Make sure the Target Runtime is set to Java Web, the Server Runtime Environment that has been created in the tutorial Configuring Eclipse with SAP Cloud Platform Tools for Java. Leave all other settings untouched and click Finish to create the project.

project wizard

The helloworld project is now ready for your code.

hello world project
Step 5: Create new servlet

In Java EE, web applications are implemented as Servlets. On the newly created helloworld project node, open the context menu with a right-click and choose New > Servlet to open the Create Servlet wizard.

open servlet wizard
Step 6: Set class name

In the Create Servlet wizard enter helloworld as Java package and HelloWorldServlet as Class name. This will create Java classes with the respective package and name. Choose Next.

create servlet wizard
Step 7: Set URL mapping

You will want this Servlet to be accessible via the URL <servername>/helloworld, for example http://localhost:8080/helloworld. For this we will set the URL mapping to \. For this select /HelloWorldServlet in the URL mappings field and choose Edit.

create servlet wizard
Step 8: Change URL pattern

In the Pattern field, replace the current value with just /. Confirm with OK.

URL mapping
Step 9: Generate servlet

Click Finish to generate the servlet.

finish servlet wizard
Step 10: Servlet opening

The Java Editor will open the corresponding HelloWorldServlet class in the editor pane. You will also find the Servlet under the helloworld project node > Java Resources > src > helloworld > HelloWorldServlet.java

servlet in editor
Step 11: Write hello world code

Next, you will edit the Servlet to output the classical “Hello World”. For this you will modify the doGet() method and add the following code and save your changes.

/**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.getWriter().println("Hello World!");
}
updated <code>doGet</code> method

The application is now ready to run.

Step 12: Run on server

To test your application before deploying it to the SAP Cloud Platform you can run it on a local runtime. To do this, do the following:

Navigate to your HelloWorldServlet.java via the helloworld project node > Java Resources > src > helloworld > HelloWorldServlet.java. Open the context menu on the Servlet with a right-click and choose the Run on Server option.

run on server
Step 13: Manually define server

Make sure that Manually define a new server is selected and choose SAP > Java Web Server as server type. Leave all other settings unchanged and click Finish.

Create local server
Step 14: View running server

A local server will start with your helloworld application deployed. After the server is ready your application will be opened in a browser within Eclipse and greet you with “Hello World!”. In the Servers view you can also see the running server with your application deployed.

App running
Step 15: Run on the SAP Cloud Platform

To run your application on the SAP Cloud Platform you will choose a different server to run it. Again, navigate to your HelloWorldServlet.java via the helloworld project node > Java Resources > src > helloworld > HelloWorldServlet.java. Open the context menu on the Servlet with a right-click and choose the Run on Server option.

run on server
Step 16: Select SAP Cloud Platform as server type

As before, make sure that Manually define a new server is selected. This time choose SAP > SAP Cloud Platform as server type. Make sure to set the Landscape host to hanatrial.ondemand.com. Leave all other settings unchanged and choose Next.

run on server - cloud

Note: The used Landscape host hanatrial.ondemand.com is only valid if you are using a free Developer Account. Please change the landscape host if you want to use a productive account. The respective landscape hosts can be found in the official documentation.

Step 17: Specify the Application name

On the next wizard page specify the Application name to be helloworld, provide the login information for your SAP Cloud Platform account and click Finish:

Field Name Value
Account Name Your SAP Cloud Platform account name, for example p1234567890trial
Username Your SAP Cloud Platform account name, for example p1234567890 and your password
app name
Step 18: View running server

A Cloud server will start that has your helloworld application deployed. After the server is ready your application will be opened in a browser in Eclipse and greet you with Hello World!. In the Servers view you can also see the running server with your application deployed

app running in HCP

Congratulations: You have your first application running on the SAP Cloud Platform!

Optional

Now that you are familiar with the basic routine of developing applications and deploying them locally and to the cloud, you may want to check out the samples provided as part of the SAP Cloud Platform SDK.

Related Information

Next Steps

Updated 09/13/2017

Time to Complete

15 Min.

Beginner

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