I just had to add input controls in the JasperServer interface, and then add these parameters.
before
http://localhost:8080/jasperserver/flow.html?_flowId=viewReportFlow&standAlone=true&_flowId=viewReportFlow&ParentFolderUri=%2Freports%2Fsamples%2FTest&reportUnit=%2Freports%2Fsamples%2FTest%2FEinReport&j_acegi_security_check&j_username=jasperadmin&j_password=jasperadmin
after
http://localhost:8080/jasperserver/flow.html?_flowId=viewReportFlow&standAlone=true&_flowId=viewReportFlow&ParentFolderUri=%2Freports%2Fsamples%2FTest&reportUnit=%2Freports%2Fsamples%2FTest%2FEinReport&j_acegi_security_check&j_username=jasperadmin&j_password=jasperadmin&Startdatum=2014-04-08&Enddatum=2014-04-11&username=firstUser
URL.
&Startdatum=2014-04-08&Enddatum=2014-04-11&username=firstUser