Jasper Reports - Error exporting the text file

I have tried to export my content to the text file using Jasper but only a empty text file is getting generated. All other formats such as pdf,xls,csv & rtf are getting generated properly. My code is as follows ,

Code :

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JRTextExporter exporter = new JRTextExporter();
exporter.setParameter(JRExporterParameter.JASPER_PRINT,jasperprint);
exporter.setParameter(JRExporterParameter.OUTPUT_FILE_NAME,stReportLocation);	
exporter.setParameter(JRTextExporterParameter.CHARACTER_WIDTH, new Float(200.00));
exporter.setParameter(JRTextExporterParameter.CHARACTER_HEIGHT, new Float(50.00));
exporter.exportReport();

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When I select file type as "text" for preview in iReport tool , there also I am getting only the blank txt file being shown.

Please suggest me the solution to generate text files using jasper.

Thanks !