How to Write CSV Files as UTF-8 for Excel

Problem

As JasperReport export CSV file with UTF-8 encoding, Microsoft Excel wasn't displaying a CSV (comma separated values) file correctly.

The screenshot is as bellows:

But it can display correctly for notepad:

Root Cause

In the absence of any charset identification, Excel must guess about a file's content encoding. Therefore, Excel uses that default to read and display CSV files.

Solution

Use the byte-order marker (BOM) to identify the CSV file as a Unicode file. So I write an byte array into OutputStream, then Excel should uses UTF-8 read and display CSV files.

1 2 3 4 5 6 7 8 9 10

//byte-order marker (BOM) byte b[] = {(byte)0xEF, (byte)0xBB, (byte)0xBF}; //insert BOM byte array into outputStream outputStream.write(b); JRExporter csvExporter = new JRCsvExporter(); csvExporter.setParameter(JRExporterParameter.JASPER_PRINT, print); csvExporter.setParameter(JRExporterParameter.OUTPUT_STREAM, outputStream); csvExporter.setParameter(JRExporterParameter.OUTPUT_FILE_NAME, reportName.concat(".csv")); csvExporter.setParameter(JRExporterParameter.CHARACTER_ENCODING, "UTF-8"); csvExporter.exportReport();

See....it's correct now!