Lessons Learned When Consuming On-Premise Service in SCP Cloud Foundry Application

Posted on | In | Views:

I am trying to follow the below links to build a SCP (SAP Cloud Platform) Cloud Foundry application which is using XSUAA (User account and authentication) service, SCP Connectivity service and SCC (SAP Cloud Connector) to consume On-Premise OData service. The below lessons are learned during the prototype.

https://blogs.sap.com/2017/07/09/how-to-use-the-sap-cloud-platform-connectivity-and-the-cloud-connector-in-the-cloud-foundry-environment-part-1/
https://blogs.sap.com/2017/07/13/part-2-how-to-use-the-sap-cloud-platform-connectivity-and-the-cloud-connector-in-the-cloud-foundry-environment/

Maven installation

  1. Install JDK and set environment variable JAVA_HOME
  2. Download Apache Maven and unzip the file
  3. Add environment variable M2_HOME and MAVEN_HOME
  4. Update environment variable PATH for Maven bin folder
  5. Run command mvn -version to verify the installation

Reference:

https://www.mkyong.com/maven/how-to-install-maven-in-windows/
http://maven.apache.org/download.cgi

Maven eclipse plugin installation

Please check the below reference links for details. Update site to install Maven plugin in Eclipse:
http://download.eclipse.org/technology/m2e/releases/

Reference:

https://stackoverflow.com/questions/8620127/maven-in-eclipse-step-by-step-installation
http://toolsqa.com/java/maven/how-to-install-maven-eclipse-ide/

Error:

Failed to read artifact descriptor for org.apache.maven.plugins:maven-resources-plugin:jar:2.6
Could not transfer artifact org.springframework.boot:spring-boot-starter-parent:pom:1.5.7.RELEASE from/to Central (http://repo1.maven.org/maven2): Connection refused: connect and ‘parent.relativePath’ points at wrong local POM

Resolution:

  1. Run the below command in Linux:
    find ~/.m2 -name "*.lastUpdated" -exec grep -q "Could not transfer" {} \; -print -exec rm {} \;
    Run the below commands in Windows
    cd %userprofile%\.m2\repository
    for /r %i in (*.lastUpdated) do del %i
    Then right click on your project in eclipse and choose Maven->Update Project ..., make sure “Update Dependencies” is checked in the resulting dialog and click OK.
  2. You can always try mvn -U clean install
    -U Forces a check for updated releases and snapshots on remote repositories
  3. There may be different versions of Maven running between command prompt and Eclipse. Check the Maven installations and Maven user settings in Eclipse -> Windows -> Preferences

Reference:

https://stackoverflow.com/questions/5074063/maven-error-failure-to-transfer

Error:

No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

Resolution:

  1. Install JDK instead of JRE
  2. Set environment variables JAVA_HOME, classpath, PATH to link them to JDK, instead of JRE
  3. Check the settings Windows -> Preferences -> Java ->Installed JREs in Eclipse. Make sure there is at least one JDK there. Link the Run configuration of Maven build to the JDK

Reference:

https://stackoverflow.com/questions/19655184/no-compiler-is-provided-in-this-environment-perhaps-you-are-running-on-a-jre-ra

Error:

The following artifacts could not be resolved: com.sap.xs2.security:java-container-security-api:jar:0.26.4, com.sap.xs2.security:java-container-security:jar:0.26.4: Failure to find com.sap.xs2.security:java-container-security-api:jar:0.26.4 in https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced

Resolution:

Install XS Security libs to your local Maven repository:

  1. The first step is to get some additional Java libs from Service Marketplace.
    Download additional XS security libs from service marketplace:https://launchpad.support.sap.com/#/softwarecenter/search/XS_JAVA
  2. Unzip the file
  3. Install XS Security Libs to your local maven repo using:
    cd <destLocation>
    mvn clean install

Reference:

https://blogs.sap.com/2017/07/18/step-7-with-sap-s4hana-cloud-sdk-secure-your-application-on-sap-cloud-platform-cloudfoundry/

Error:

The import org.json cannot be resolved
The import org.apache.commons.io cannot be resolved

Resolution:

  1. Download the ZIP file from the below URL and extract it to get the Jar.

  2. Add the Jar to your build path. To Add this Jar to your build path Right click the Project > Build Path > Configure build path > Select Libraries tab > Click Add External Libraries > Select the Jar file downloaded

http://www.java2s.com/Code/JarDownload/java/java-json.jar.zip
http://commons.apache.org/proper/commons-io/download_io.cgi

Reference

https://stackoverflow.com/questions/8997598/importing-json-into-an-eclipse-project

Error

package json.java does not exist
package org.apache.commons.io does not exist

Resolution

  1. Run the below Maven command to install the Maven repository
    mvn install:install-file -Dfile=java-json.jar -DgroupId=json.java -DartifactId=java-json -Dversion=1.0 -Dpackaging=jar
    mvn install:install-file -Dfile=commons-io-2.6.jar -DgroupId=commons-io -DartifactId=commons-io -Dversion=2.6 -Dpackaging=jar
  2. Add the below dependencies to the pom.xml file
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    <dependency>
    	<groupId>json.java</groupId>
    	<artifactId>java-json</artifactId>
    	<version>1.0</version>
    	<scope>compile</scope>
    </dependency>
    <dependency>
    	<groupId>commons-io</groupId>
    	<artifactId>commons-io</artifactId>
    	<version>2.6</version>
    	<scope>compile</scope>
    </dependency>

Reference

https://stackoverflow.com/questions/41779195/maven-compilation-error-even-if-dependency-path-is-correct

Error

Cannot instantiate the type XSTokenRequest

Resolution

  1. Run the below command to install the Jar file to local Maven repository
    mvn install:install-file -Dfile=java-container-security-api-0.26.4.jar -DgroupId=com.sap.xs2.security -DartifactId=java-container-security-api -Dversion=0.26.4 -Dpackaging=jar
    mvn install:install-file -Dfile=java-container-security-0.26.4.jar -DgroupId=com.sap.xs2.security -DartifactId=java-container-security -Dversion=0.26.4 -Dpackaging=jar
  2. Change the pom.xml with the below:
    <dependency>
      <groupId>com.sap.xs2.security</groupId>
      <artifactId>java-container-security-api</artifactId>
      <version>0.26.4</version>
</dependency>
<dependency>
    <groupId>com.sap.xs2.security</groupId>
    <artifactId>java-container-security</artifactId>
     <version>0.26.4</version> 
</dependency>
  3. Run Maven update for the project
  4. Check the build path for the Java file to see if multiple libraries are used

Error

The import javax.servlet can’t be resolved [duplicate]

Resolution

You need to add the Servlet API to your classpath. In Tomcat 6.0, this is in a JAR called servlet-api.jar in Tomcat’s lib folder. You can either add a reference to that JAR to the project’s classpath, or put a copy of the JAR in your Eclipse project and add it to the classpath from there.

Reference

https://stackoverflow.com/questions/4119448/the-import-javax-servlet-cant-be-resolved

Error:

Unable to extract request URI: URI must contain a host
http://<virtual_host>:80/sap/opu/odata/sap/<odata_service>//$metadata

Resolution:

Update the SCC (SAP Cloud Connector) and SCP destination to make sure underscore is not used in the hostname

How to change the font size in Eclipse editor

Windows -> Preferences -> General -> Appearance -> Color and Fonts -> Basic -> Text Font -> Edit -> Apply

How to search for a string in a project in Eclipse

Ctrl + H

How to upload a project over 20M to SCP CF environment

Use Eclipse Cloud Foundry plugin