文件上传与下载

1. 文件上传

　　关键代码：

     public void save(File cenclosure,Collectfile collectfile) {
        try {
            InputStream inputStream = new FileInputStream(cenclosure);
            collectfile.setCenclosure(inputStream);
            String name = cenclosure.getName();
            collectfile.setCmenclosure(name);
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        if (Validation.hasErrors()) {
            this.printError(Validation.getErrorsAsString());
            return;
        }
        collectfileService.save(collectfile);
    }

　　注意事项：

　　1.其中参数 cenclosure 要和前端form表单中的参数名称一致，否则无法上传

　　2.将File类型转换成流的形式，数据库中以二进制的形式存储

2. 文件下载

　　关键代码：

/**
     * 文件下载
     * @param omenclosure  文件名
     * @throws IOException 
     */
    public void downloadLocal(String id){
        try {
            //根据编号查询得到实体类对象
            Collectfile collectfile = (Collectfile) collectfileService.findById(id);
            
            HttpServletResponse response = response();
            
            //获取InputStrem流
            InputStream in = collectfile.getCenclosure();
            response.setContentType("application/x-msdownload");
            response.addHeader("Content-Disposition", "attachment; filename="+new String(collectfile.getCmenclosure().getBytes("gb2312"),"iso-8859-1"));
            OutputStream out =response.getOutputStream();
            byte[] b = new byte[1024];
            int l;
            while((l = in.read(b)) != -1){
                out.write(b, 0, l);
            }
            in.close();
            out.flush();
            out.close();
            
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }