java 65533,java导出excel超出65533行
业务背景：
列表导出，数据导出超过65533行
解决方案：
1、超出65533行，直接系统提示：本系统支持导出的最大条数为65533行
2、导出模版改为.xlsx，POI导出时用XSSFWorkbook，把所有数据都拿到内存里，可以导出超过65533行，但是上线之后，发现会内存溢出
3、导出模版改为.xlsx，POI导出时用SXSSFWorkbook，每次往内存里放一定的数据，导完之后，刷新，再次从磁盘往内存放数据，会产生临时文件，导出完成之后，需把临时文件删掉，这种方式会使CPU短暂升高，但是很快会降下去
private static ByteArrayInputStream WriteToExcelTemplate(DataModel dataModel, HttpServletRequest request) {
String template = getRealPathModelExcel(dataModel.getTemplate(), request);
FileInputStream fileInputStream = new FileInputStream(template);
XSSFWorkbook workBook = new XSSFWorkbook(fileInputStream);
int rowaccess = 100;
SXSSFWorkbook wb = new SXSSFWorkbook(workBook,rowaccess);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
Sheet sh = wb.getSheetAt(0);
List data = dataModel.getData();
int startRow = dataModel.getStartRow();
for (int i = 0; i < data.size(); ++i) {
Object[] objArray = (Object[]) data.get(i);
Row row = sh.createRow(startRow);
Cell[] cell = new SXSSFCell[objArray.length];
for (int j = 0; j < objArray.length; ++j) {
cell[j] = row.createCell(j);
cell[j].setCellStyle(dataModel.getCenterStyle());
if (objArray[j] == null) {
cell[j].setCellValue("");
} else {
setCellValue(cell[j], objArray[j]);
}
}
++startRow;
if(i%rowaccess==0){
((SXSSFSheet)sh).flushRows();
}
}
wb.write(byteArrayOutputStream);
byte[] byteArray = byteArrayOutputStream.toByteArray();
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArray);
byteArrayOutputStream.close();
deleteSXSSFTempFiles(wb);//删除临时文件
return byteArrayInputStream;
}
/**
* 删除临时文件
* @param workbook
* @throws NoSuchFieldException
* @throws IllegalAccessException
*/
public static void deleteSXSSFTempFiles(SXSSFWorkbook workbook)
throws NoSuchFieldException, IllegalAccessException {
int numberOfSheets = workbook.getNumberOfSheets();
// iterate through all sheets (each sheet as a temp file)
for (int i = 0; i < numberOfSheets; i++) {
Sheet sheetAt = workbook.getSheetAt(i);
// delete only if the sheet is written by stream
if (sheetAt instanceof SXSSFSheet) {
SheetDataWriter sdw = (SheetDataWriter) getPrivateAttribute(sheetAt, "_writer");
File f = (File) getPrivateAttribute(sdw, "_fd");
try {
f.delete();
} catch (Exception ex) {
// could not delete the file
}
}
}
}
public static Object getPrivateAttribute(
Object containingClass, String fieldToGet)
throws NoSuchFieldException, IllegalAccessException{
// get the field of the containingClass instance
Field declaredField = containingClass.getClass().getDeclaredField(fieldToGet);
declaredField.setAccessible(true); // access it
Object get = declaredField.get(containingClass); // return it!
return get;
}
标签：java,get,int,导出,Object,excel,cell,new,65533
来源： https://blog.csdn.net/weixin_43805526/article/details/90415248