以A4纸为例：
excel默认A4纸大小 =210mm×297mm,换算成excel默认单位 A4=610×850
1.定义列宽 width
2.获取当前列的数据长度 length = str.getBytes().length;
/*默认行高*/ short height = 15; /*页行高*/ double rowheight = 0;/*定义一个list*/List<Double> dous = new ArrayList<Double>();/*将每一列的数据计算出行高*/dous.add(Math.ceil((float)(length )/(sheet.getColumnWidth(cellNum)/256))*height)/*预测行高*/double virtualTotalHeight = rowHeight + Collections.max(dous);/*预测行高：如果virtualTotalHeight大于A4高度则下一页开启，否则继续当前页*/if(isPage(virtualTotalHeight)){HSSFRow row = sheet.createRow(rowNum);/*将dous中最大的值设定为行高*/row.setHeightInPoints(Collections.max(dous).intValue());/*统计总行高*/ rowHeight = rowHeight + Collections.max(dous);/*分页符*/sheet.setRowBreak(rowNum);}else{/*下一页*/rowHeight = 0;HSSFRow row = sheet.createRow(rowNum);/*将dous中最大的值设定为行高*/row.setHeightInPoints(Collections.max(dous).intValue());/*统计总行高*/ rowHeight = rowHeight + Collections.max(dous);}
/*** 判断添加一行是否大于A4纸高度* @param height* @return*/public static boolean isPage(double height){boolean flag = false;/*A4纵向纸高度*/double A4_lengthways_pageSize = 828;//纵向转换成点 （293/4.5）*12.75/*A4横向纸高度*/double A4_crosswise_pageSize = 600;//横向转换成点if((A4_crosswise_pageSize-height)> 30){flag = true;}else {flag = false;}return flag ;}
/*** sheet默认设置* @param sheet*/public static void settingDefault(HSSFSheet sheet,boolean flag){//设置不显示网格线sheet.setDisplayGridlines(false);//默认列宽sheet.setDefaultColumnWidth(8);/*设置打印页面为水平居中*/sheet.setHorizontallyCenter(true);/**默认行高*/sheet.setDefaultRowHeightInPoints((short)15);/*设置页边距*/sheet.setMargin(HSSFSheet.TopMargin,(short) 0.6);sheet.setMargin(HSSFSheet.BottomMargin,(short) 0.6);sheet.setMargin(HSSFSheet.LeftMargin,(short) 0.2);sheet.setMargin(HSSFSheet.RightMargin,(short) 0.2);/*置顶*/sheet.setVerticallyCenter(false);/*打印设置*/HSSFPrintSetup printSetup = sheet.getPrintSetup();if(flag){/*默认横向打印*/printSetup.setLandscape(true);/*页高设置*/printSetup.setFitHeight((short)610);}else {/*默认纵向打印*/printSetup.setLandscape(false);/*页高设置*/printSetup.setFitHeight((short)850);}//A4纸printSetup.setPaperSize(HSSFPrintSetup.A4_PAPERSIZE);}
