无法写入数据，文档似乎已经关闭

Question

将数据写入XSSFWorkbook文件时出现异常：

java.io.IOException: Cannot write data, document seems to have been closed already
    at org.apache.poi.POIXMLDocument.write(POIXMLDocument.java:215)

这是我的代码：

List<Object[]> rows = query.getResultList();

for (Object[] row : rows) {
{
    Row crow = sheet.createRow(rowNum++);

    for (int i = 0; i < row.length; i++) {
        crow.createCell(i).setCellValue(String.valueOf(row[i]));
    }
}

// Write the output to a file
FileOutputStream fileOut = new FileOutputStream(FilePath);
workbook.write(fileOut);
fileOut.close();