jabrown

Yes, Jaspersoft Server's REST API allows for report execution with POST using the reportExecutions service.
I've attached the following HTTP request sample of this using Postman.  The first request is a synchronous request to execute the report.  It returns the necessary request and export information.  The second request retrieves the report output from the previous execution.  You can choose to run an asynchronous request for longer running reports if preferred.
POST /jasperserver-pro79/rest_v2/reportExecutions HTTP/1.1Host: localhost:8080Authorization: Basic c3VwZXJ1c2VyOnN1cGVydXNlcg==Content-Type: application/xmlCookie: userLocale=en_US; JSESSIONID=9E0BBE880F49C7987CAE6C4E43252641Content-Length: 509<reportExecutionRequest> <reportUnitUri>/public/Samples/Reports/01._Geographic_Results_by_Segment_Report</reportUnitUri> <async>false</async> <freshData>false</freshData> <saveDataSnapshot>false</saveDataSnapshot> <outputFormat>html</outputFormat> <interactive>true</interactive> <ignorePagination>true</ignorePagination> <parameters> <reportParameter name="Country"> <value>USA</value> </reportParameter> </parameters></reportExecutionRequest>[/code]GET /jasperserver-pro79/rest_v2/reportExecutions/ad0edbf2-abd2-4ebe-8344-b2e453eab496/exports/79662286-aa90-4e98-a732-337ab5ee0504/outputResource HTTP/1.1Host: localhost:8080Authorization: Basic c3VwZXJ1c2VyOnN1cGVydXNlcg==Cookie: userLocale=en_US; JSESSIONID=9E0BBE880F49C7987CAE6C4E43252641[/code] 

Hello,
You should be able achieve this by using the following expression for your text field.  I belive the Java function you'll want to use is replace rather than split.  You will replace your defined character with a new line.
"AB/CD/E/F/".replace("/","rn")
Your JRXML for the text field value will be as follows.
<textFieldExpression><![CDATA["AB/CD/E/F/".replace("/","rn")]]></textFieldExpression>
I hope this helps solve your challenege!