HSSFWorkbook导出excel时会有65535行的限制，当我们数据量大的时候可以分多个sheet页的方案来解决，
但是每个sheet页都需要读取下载模版文件的表头，而poi库对一个excel之间的多sheet页都读取模版excel文件不支持，
本文的思路是先生成多个excel文件到内存，然后再将这些excel复制到一个文件的多个sheet页中。
一 . 首先查出来数据总数，按6万条一个excel进行生成。
//生成excel
@GetMapping("/generate")
public void generate(String fileName){
List<Map<String,Object>> dataList=new ArrayList();
//测试数据
for (int i=0;i<200000;i++){
Map m1 = new HashMap();
m1.put("Zara", "8bbb");
m1.put("Mahnaz", "31cc");
m1.put("Ayan", "12");
m1.put("Daisy", "14111aa");
dataList.add(m1);
}
//单个sheet处理65536条最多
final int sheetNum= new Double(Math.ceil((float)dataList.size()/60000)).intValue();
HSSFWorkbook sumWorkBook =new HSSFWorkbook();
for (int i=0;i<sheetNum;i++){
HSSFWorkbook workbook1=exportExcelByPostFix(dataList.subList(60000*i,
(i!=(sheetNum-1)?(60000*(i+1)):dataList.size())));
HSSFSheet sheet1=workbook1.getSheetAt(0);
HSSFSheet newsheet =sumWorkBook.createSheet("sheet"+(i+1));
ExcelUtil.copySheet(sumWorkBook,sheet1,newsheet);
}
//生成文件
exportFile(sumWorkBook,fileName);
return Result.succ("copy");
}
二 . 将每6万条数据生成一个excel到内存中，即excel的第一个sheet页
public HSSFWorkbook exportExcelByPostFix(List<Map<String,Object>> dataList){
//获取模版表头
Resource resourceData=new DefaultResourceLoader().getResource("classpath:doctemp/temp.xls");
InputStream inputStream=null;
HSSFWorkbook wb=null;
try {
//获取输入流
inputStream= resourceData.getInputStream();
//创建带表头的工作表
wb=new HSSFWorkbook(inputStream);
//设置单元格基础样式，加边框，加基础黑框
CellStyle hssfCellStyle=wb.createCellStyle();
hssfCellStyle.setBorderBottom(BorderStyle.THIN);
hssfCellStyle.setBorderLeft(BorderStyle.THIN);
hssfCellStyle.setBorderRight(BorderStyle.THIN);
hssfCellStyle.setBorderTop(BorderStyle.THIN);
//字居中
hssfCellStyle.setAlignment(HorizontalAlignment.CENTER);
//获取第一个sheet页
HSSFSheet sheet=wb.getSheetAt(0);
//前五行表头
int count=5;
ExcelUtil.exportForData(dataList,sheet,hssfCellStyle,count);
}
catch (IOException e){
}
finally {
}
return wb;
}
三.生成excel工具类，以及复制sheet页的方法
public class ExcelUtil {
/**
* sheet复制
*/
public static void copySheet(HSSFWorkbook wb, HSSFSheet fromSheet, HSSFSheet toSheet){
//合并区域处理
mergeSheetAllRegion(fromSheet, toSheet);
// 列宽
int length = fromSheet.getRow(fromSheet.getFirstRowNum()).getLastCellNum();
for (int i = 0; i <= length; i++) {
toSheet.setColumnWidth(i, fromSheet.getColumnWidth(i));
}
int flag=0;
//设置单元格基础样式，加边框，加基础黑框
CellStyle hssfCellStyle=wb.createCellStyle();
hssfCellStyle.setBorderBottom(BorderStyle.THIN);
hssfCellStyle.setBorderLeft(BorderStyle.THIN);
hssfCellStyle.setBorderRight(BorderStyle.THIN);
hssfCellStyle.setBorderTop(BorderStyle.THIN);
//字居中
hssfCellStyle.setAlignment(HorizontalAlignment.CENTER);
for (Iterator rowIt = fromSheet.rowIterator(); rowIt.hasNext(); ) {
HSSFRow oldRow = (HSSFRow) rowIt.next();
HSSFRow newRow = toSheet.createRow(oldRow.getRowNum());
flag++;
copyRow(wb, oldRow, newRow,flag,hssfCellStyle);
}
}
/**
* 行复制
*/
private static void copyRow(HSSFWorkbook wb, HSSFRow oldRow, HSSFRow toRow,int flag,
CellStyle hssfCellStyle) {
toRow.setHeight(oldRow.getHeight());
for (Iterator cellIt = oldRow.cellIterator(); cellIt.hasNext(); ) {
HSSFCell tmpCell = (HSSFCell) cellIt.next();
HSSFCell newCell = toRow.createCell(tmpCell.getColumnIndex());
copyCell(wb, tmpCell, newCell,flag,hssfCellStyle);
}
}
/**
* 合并单元格处理
*/
private static void mergeSheetAllRegion(HSSFSheet fromSheet, HSSFSheet toSheet) {
int sheetMergeCount = fromSheet.getNumMergedRegions();
CellRangeAddress cellR = null;
for (int i = 0; i < sheetMergeCount; i++) {
cellR = fromSheet.getMergedRegion(i);
toSheet.addMergedRegion(cellR);
}
}
/**
* 复制单元格
*/
private static void copyCell(HSSFWorkbook wb, HSSFCell fromCell, HSSFCell toCell, int flag,
CellStyle hssfCellStyle) {
//excel表头有5行
if(flag<6){
HSSFCellStyle newstyle = wb.createCellStyle();
// 复制单元格样式
newstyle.cloneStyleFrom(fromCell.getCellStyle());
// 样式
toCell.setCellStyle(newstyle);
}
else {
//其它的单元格用标准格式
//单元格格式过多会抛出异常，不支持创建太多
toCell.setCellStyle(hssfCellStyle);
}
if (fromCell.getCellComment() != null) {
toCell.setCellComment(fromCell.getCellComment());
}
// 不同数据类型处理
CellType fromCellType = fromCell.getCellType();
toCell.setCellType(fromCellType);
if (fromCellType == CellType.NUMERIC) {
if (DateUtil.isCellDateFormatted(fromCell)) {
toCell.setCellValue(fromCell.getDateCellValue());
} else {
toCell.setCellValue(fromCell.getNumericCellValue());
}
} else if (fromCellType == CellType.STRING) {
toCell.setCellValue(fromCell.getRichStringCellValue());
} else if (fromCellType == CellType.BLANK) {
// nothing21
} else if (fromCellType == CellType.BOOLEAN) {
toCell.setCellValue(fromCell.getBooleanCellValue());
} else if (fromCellType == CellType.ERROR) {
toCell.setCellErrorValue(fromCell.getErrorCellValue());
} else if (fromCellType == CellType.FORMULA) {
toCell.setCellFormula(fromCell.getCellFormula());
} else {
// nothing29
}
}
/**
* 创建单元格
*/
public static void createCell(Row rows,int column,String value,CellStyle hssfCellStyle){
Cell cell=rows.createCell(column);
cell.setCellValue(value);
cell.setCellStyle(hssfCellStyle);
}
/**
* 根据数据组装cell数据
* count=5表示从第6行开始生成单元格，前面5行是表头
*/
public static void exportForData(List<Map<String,Object>> list, HSSFSheet hssfSheet,
CellStyle hssfCellStyle,int count){
if(list!=null&& list.size()!=0){
for (int i=0;i<list.size();i++){
//创建行
Row rows=hssfSheet.createRow(count);
Map<String,Object> map= list.get(i);
//是否总计数据
int j=0;
Set<String> sets= map.keySet();
if(sets==null||sets.size()<1){
continue;
}
for (String key:sets){
createCell(rows,j,String.valueOf(map.get(key)),hssfCellStyle);
//在for循环中。单元格纬度下调用该函数，会极大降低效率
//所以在最后一行数据时，才调用这个函数
if(i==list.size()-1){
hssfSheet.autoSizeColumn(j);//按内容撑开单元格宽度
}
j++;
}
count++;
}
}
}
}
四,将生成的每个excel的sheet1合并到一个总的excel中，代码在第一步已经列出。然后生成文文件
private void exportFile(HSSFWorkbook workbook,String fileName){
String c="/workspace/java/";
File file=new File(c);
if(!file.exists()){
file.mkdir();
}
String exportFilePath=file +"/"+fileName+".xls";
FileOutputStream outputStream=null;
try {
outputStream =new FileOutputStream(exportFilePath);
workbook.write(outputStream);
outputStream.flush();
}
catch (Exception e){
}
finally {
}
}
五，结束。需要注意的是window开发环境和部署的linux环境的差别