Exercise: Querying SAP APIs in a Java program

In your Windows laptop, in the File Explorer, create a project folder with name java-call-api (if you are in the SAP training system, use D:\workspace\java-call-api). Extract the content of thejava-call-api-initial.zip archive [download] to the project folder.

Open the project folder using your preferred Java IDE (such as, IntelliJ IDEA or Visual Studio Code). Run the App.main() method. [play]

1. Open your IDE (IntelliJ IDEA or Visual Studio Code). Within your IDE, open your project folder. Check the status bar of your Java IDE (lower right corner of the window) until the analysis (build) of the project is complete.

2. Open the src/main/java/com/example/App.java file and review the code. Run the App.main() method (for IntelliJ IDEA, select the green arrow on the left border of the editor, beside the method definition, for Visual Studio Code, choose the Run button just before the definition of the method). A terminal window appears and the program is executed. "Hello World!" is printed in the Terminal.

Open the SAP Business Application Studio, open the training development space. [play]

1. In your Web browser (for example, Google Chrome), open https://account.hanatrial.ondemand.com. If requested, enter your user and password.

2. Choose SAP Business Application Studio.

3. Enter the training development space.

In the SAP Business Application Studio, create a new project folder named java-call-api, open it as a workspace, import in it the content of the java-call-api-initial.zip archive. Build the maven project.[play]

1. Choose File → Open Workspace... (Ctrl+Alt+W), choose the projects folder and choose Open.

2. In the Projects tab, right click and create a sub folder with name java-call-api.

3. Choose File → Open Workspace... (Ctrl+Alt+W), choose the projects/java-call-api folder and choose Open.

4. In the java-call-api tab, right-click and choose Upload Files..., browse to the java-call-api-initial.zip file, and choose Open.

5. Choose Terminal → New Terminal. A terminal window appears in the lower part of the screen.

6. In the terminal, execute the following command:

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   unzip *.zip

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   The archive content is extracted to the local folder. Execute the following command to remove the archive:

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   rm *.zip

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   Execute the following command to build the maven project:

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   mvn clean install

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Choose which IDE you want to use for the following steps. You can choose SAP Business Application Studio, or Intellij IDEA, or Visual Studio Code. Open the project in your development environment, optionally enable source control to better follow code changes in the next steps. [play]

In you IDE of choice, run the App.main() method. [play]

1. Open the src/main/java/com/example/App.java file and review the code.

2. If you are using SAP Business Application Studio or Visual Studio Code, choose the Run button just before the definition of the method (it may require a few seconds before Run appears).

3. if you are using IntelliJ IDEA, choose the green arrow on the left border of the editing area and choose Run App.main()

   Note

   In case you are requested to choose the project type, between Eclipse and Maven. You must choose Maven.

4. The Debug Console (or the Run window ) is opened and Hello World appears in it.

Modify the project so that the App.main() method reads the service using the SAP Cloud SDK. Extract the BUSINESS_PARTNER, LAST_NAME, FIRST_NAME for all the Business Partners whose first name begins with letter E. [play]

1. Search and add the latest version of the following Java libraries to the pom.xml file in your project:

   Group ID	Artifact ID
   com.sap.cloud.sdk.s4hana	s4hana-all

   If you encounter an issue, replace the content of the whole pom.xml file with the content of the java-call-api-1-pom.txt file [download], provided in the exercise files.

2. Replace the whole Main.App() method with the following (in the code, replace the ">>>YOUR APIKEY<<<" string with your API Key, for example, "FDqbnElM7mgmgqbIKBFHRpS1dvpt6sHD"):

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   public static void main(String[] args) throws ODataException {
   
       // Create the destination class
       HttpDestination destination = DefaultDestination.builder()
           .property("Name", "SANDBOX")
           .property("URL", "https://sandbox.api.sap.com/s4hanacloud")
           .property("Type", "HTTP")
           .property("Authentication", "NoAuthentication")
           .build().asHttp();
   
       // Preparing the query to the Business Partner service
       final BusinessPartnerService service =
               new DefaultBusinessPartnerService();
       BusinessPartnerFluentHelper helper =
           service.getAllBusinessPartner()
               .select(
                   BusinessPartner.BUSINESS_PARTNER,
                   BusinessPartner.LAST_NAME,
                   BusinessPartner.FIRST_NAME)
               .filter(
                   BusinessPartner.FIRST_NAME.ge("E")
                       .and(BusinessPartner.FIRST_NAME.lt("F")));
   
       // Setting the API Key in the request header (required for the
       // SAP API Business Hub sandbox system, not required for
       // S/4HANA Cloud).
       helper.withHeader("apikey", ">>>YOUR APIKEY<<<");
   
       // Running the query
       List<BusinessPartner> list = helper.executeRequest(destination);
   
       // Print out the result in a pretty JSON format.
       System.out.println(new GsonBuilder().disableHtmlEscaping()
               .setPrettyPrinting().create().toJson(list));
   }

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   To get the code, replace the content of the whole App.java file with the content of the java-call-api-1-app.txt file [download], provided in the exercise files (in the code, replace the ">>>YOUR APIKEY<<<" string with your API Key, for example, "FDqbnElM7mgmgqbIKBFHRpS1dvpt6sHD").

3. Run the App.main() method. A list of business partners is extracted and displayed in the terminal window (or in the Debug Console).

   Note

   In the SAP Business Application Studio you may need to re-build the project. To do that, switch to the terminal window and run:

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   mvn clean install

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Modify the project to query your S/4HANA Cloud system, accessible via the following information (replace ### with your user number):

Information	Value
URL	Your S/4HANA Client tenant URL, for example https://my000000.s4hana.ondemand.com
Service user name	ADDRESS_MANAGER_###
Password	WelcomeToTheClouds1!

Note

As a prerequisite for this API to be accessible in the S/4HANA Cloud tenant, you need to execute the previous exercise: Activating the APIs in SAP S/4HANA Cloud.

1. In the Main.App() method, change the system information in the following lines:

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   HttpDestination destination = DefaultDestination.builder()
        .property("Name", "SANDBOX")
       .property("URL", "https://sandbox.api.sap.com/s4hanacloud")
       .property("Type", "HTTP")
       .property("Authentication", "NoAuthentication")
        .build().asHttp();

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   with the following new values (replace ### with your user number and replace the URL with your own tenant URL):

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   HttpDestination destination = DefaultDestination.builder()
       .property("Name", "S4CLOUD")
       .property("URL", "https://my000000.s4hana.ondemand.com")
       .property("Type", "HTTP")
       .property("Authentication", "BasicAuthentication")
       .property("User", "ADDRESS_MANAGER_###")
       .property("Password", "WelcomeToTheClouds1!")
       .build().asHttp();

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   In addition, you can remove the following code that is required for the sandbox, but not required in case of basic authentication:

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   // Setting the API Key in the request header (required for the
   // SAP API Business Hub sandbox system, not required for
   // S/4HANA Cloud).
   helper.withHeader("apikey", ">>>YOUR APIKEY<<<");

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   You can copy the content of the whole App.java from the java-call-api-2-app.txt file, provided in the exercise files (in the code, replace the ">>>YOUR APIKEY<<<" string with your API Key, for example, "FDqbnElM7mgmgqbIKBFHRpS1dvpt6sHD").

2. Run the App.main() method.