jxl直接更新execl某一格的数据

//创建只读的Excel工作薄的对象
jxl.Workbook rw = jxl.Workbook.getWorkbook(new File(sourcefile));
//创建可写入的Excel工作薄对象
jxl.write.WritableWorkbook  wwb = Workbook.createWorkbook(new File(targetfile), rw);
            
//读取第一张工作表
jxl.write.WritableSheet ws = wwb.getSheet(0);
//获得第一个单元格对象
jxl.write.WritableCell wc = ws.getWritableCell(0, 0);
            
//判断单元格的类型, 做出相应的转化
if(wc.getType() == CellType.LABEL)
{
Label l = (Label)wc;
    l.setString("The value has been modified.");
}
//写入Excel对象
wwb.write();
//关闭可写入的Excel对象
wwb.close();
//关闭只读的Excel对象
rw.close();