Service层怎么写导出Excel方法？？？
已经跟dao连接：private HardwareDao dao;
导出方法：
public String exportExcel() {
HSSFWorkbook wb=new HSSFWorkbook();
HSSFSheet sheet=wb.createSheet("计算机信息表");
HSSFRow row=sheet.createRow((int)0);
HSSFCellStyle style=wb.createCellStyle();
style.setAlignment(HSSFCellStyle.ALIGN_CENTER);

HSSFCell cell=row.createCell((short)0);
cell.setEncoding(HSSFCell.ENCODING_UTF_16);
cell.setCellValue("计算机名");
cell.setCellStyle(style);
cell=row.createCell((short)1);
cell.setCellValue("IP");
cell.setCellStyle(style);
cell=row.createCell((short)2);
cell.setCellValue("MAC");
cell.setCellStyle(style);
cell=row.createCell((short)3);
cell.setCellValue("操作系统版本");
cell.setCellStyle(style);
cell=row.createCell((short)4);
cell.setCellValue("网卡");
cell.setCellStyle(style);
cell=row.createCell((short)5);
cell.setCellValue("内存");
cell.setCellStyle(style);
cell=row.createCell((short)6);
cell.setCellValue("硬盘");
cell.setCellStyle(style);
cell=row.createCell((short)7);
cell.setCellValue("CPU");
cell.setCellStyle(style);
cell=row.createCell((short)8);
cell.setCellValue("显卡");
cell.setCellStyle(style);

List<PcHardwareInfo> list=dao.getAllPCInfo();

PcHardwareInfo phw;
row=sheet.createRow((int)1);
phw=(PcHardwareInfo) list.get(1);
row.createCell((short)0).setCellValue(phw.getPcname());
row.createCell((short)1).setCellValue(phw.getIp());
row.createCell((short)2).setCellValue(phw.getMac());
row.createCell((short)3).setCellValue(phw.getOs());
row.createCell((short)4).setCellValue(phw.getNet());
row.createCell((short)5).setCellValue(phw.getMemory());
row.createCell((short)6).setCellValue(phw.getHarddisk());
row.createCell((short)7).setCellValue(phw.getCpu());
row.createCell((short)8).setCellValue(phw.getGraphics());

try{
FileOutputStream fout=new FileOutputStream("F:/计算机设备信息");
wb.write(fout);
fout.close();
}catch(Exception e){
e.printStackTrace();
}
return "";
}

dao.getAllPCInfo();这一行是取数据库PC所有信息

请问这样写代码有什么问题吗？dao要实例化吗？如果要应该怎么做？？

[解决办法]
比如这样写

Java code

public class People{   // private  Templeate  temp;        public  People(){        System.out.println("--PEOPLE----实例化了----------");    }    private ManagerDao  managedao;    public ManagerDao getManagedao()    {        return managedao;    }    public void setManagedao(ManagerDao managedao) //这个方法必须有，因为采用的是set方式注入    {                   System.out.println("======");        this.managedao = managedao;    }   public class ManagerDao// extends HibernateDaoSupport{               public  String save(){         System.out.println("==============save============");         return  "hhhh";     }          public void saveOrUpdateObject(Object obj) {         //getHibernateTemplate().saveOrUpdate(obj);           return ;     }            }}