java在web端直接输出Excel实现下载的代码

下面代码段是关于 java在web端直接输出Excel实现下载的代码，应该对大伙有用途。

public String excelDomnload() throws Exception{
        try{
            String path = GlobalKeys.getFunctionConfig("user_attach_save","/opt/tmp/");
            RegUser ru = ((RegUserLoginInfo) request.getSession().getAttribute(GlobalKeys.REG_USER_IN_SESSION_NAME)).getRegUser();
            String tmpPath = File.separator + "import" + File.separator
            + ru.getName() + File.separator;
            String fName = request.getParameter("fName");
            response.setContentType("application/msexcel;");              
            response.setHeader("Content-Disposition", new String(("attachment;filename="+"error.xls").getBytes("GB2312"), "UTF-8"));

            File f = new File("d:/20121211165820140_err.xls");
            FileInputStream in = new FileInputStream(f);
            byte b[] = new byte[1024];
            int i = 0;
            ServletOutputStream out = response.getOutputStream();
            while((i=in.read(b))!=  -1){
                out.write(b, 0, i);
            }
            out.flush();
            out.close();
            in.close();
        }catch(Exception e){
            e.printStackTrace();
        }
        return null;
    }