/**設定單元格格式為文字格式*/
HSSFCellStyle textStyle = workBook.createCellStyle();
HSSFDataFormat format = workBook.createDataFormat();
textStyle.setDataFormat(format.getFormat("@"));
cell.setCellStyle(textStyle);//設定單元格格式為"文字"
cell.setCellType(HSSFCell.CELL_TYPE_STRING); 

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CellStyle textStyle = wb.createCellStyle();

DataFormat  format = wb.createDataFormat();

textStyle.setDataFormat(format.getFormat("@"));

sheet.setDefaultColumnStyle(colNum, textStyle);