EasyExcel.write(outputStream,xxxExcelModel.class).registerWriteHandler(horizontalCellStyleStrategy).registerWriteHandler(new ExcelWidthStyleStrategy()).sheet("xxxsheet1").doWrite(xxxList);

样式

private WriteCellStyle getHeadStyle(){
    //头设置
    WriteCellStyle writeCellStyle = new WriteCellStyle();
    writeCellStyle.setFillBackgroundColor(IndexedColors.RED.index);
    writeCellStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.index);
    writeCellStyle.setFillPatternType(FillPatternType.SOLID_FOREGROUND);
    //字体
    WriteFont writeFont = new WriteFont();
    writeFont.setFontHeightInPoints((short)11);
    writeCellStyle.setWriteFont(writeFont);
    writeCellStyle.setShrinkToFit(true);
    return writeCellStyle;
}

表头字段宽度

class ExcelWidthStyleStrategy extends AbstractColumnWidthStyleStrategy{

    @Override
    protected void setColumnWidth(WriteSheetHolder writeSheetHolder, List<CellData> list, Cell cell, Head head, Integer integer, Boolean aBoolean) {

        Sheet sheet = writeSheetHolder.getSheet();
        sheet.setColumnWidth(cell.getColumnIndex(),4000);
    }
}