java中poi怎么生成excel

java中我想用poi生成Excel？

怎么用？

网上好多啊

我给你找了一个例子

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public static void main(String[] args) {
try {
String filepath = "d:\\问题清单.xls";
FileInputStream fis = new FileInputStream(filepath);
// POIFSFileSystem pfs = new POIFSFileSystem(new FileInputStream("d:\\OA问题清单.xls"));
// HSSFWorkbook hwb = new HSSFWorkbook(pfs);
HSSFWorkbook hwb = new HSSFWorkbook(fis);
// HSSFSheet hws = hwb.getSheetAt(0);
HSSFSheet hws = hwb.getSheet("问题清单");
HSSFRow row = hws.getRow(2);
HSSFCell cell = null;
cell = row.getCell((short) 1);
System.out.println("cellnumber:"+cell.getCellNum());
System.out.println("cellvalue:"+getExcelCellValue(cell));
cell.setCellValue(new Date());
cell = row.getCell((short)2);
HSSFRichTextString rts = new HSSFRichTextString("输入");
cell.setCellValue(rts);
FileOutputStream fos = new FileOutputStream(filepath);
hwb.write(fos);
fis.close();
fos.close();
} catch (FileNotFoundException ex) {
Logger.getLogger(poi.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(poi.class.getName()).log(Level.SEVERE, null, ex);
}

}

public static String getExcelCellValue(HSSFCell cell) {
String ret = "";
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
DecimalFormat df = new DecimalFormat("#");
int celltype = cell.getCellType();
switch(celltype){
case HSSFCell.CELL_TYPE_NUMERIC:
if(HSSFDateUtil.isCellDateFormatted(cell)){
ret = sdf.format(cell.getDateCellValue());
}else{
ret = df.format(cell.getNumericCellValue());
}
break;
case HSSFCell.CELL_TYPE_STRING:
ret = cell.getRichStringCellValue().toString();
break;
default:

}
return ret;
}