文件上传方式二

    public String upload(){
             
        InputStream is=null;
        OutputStream os=null;
        try {
          is=new FileInputStream(file);
          String path=ServletActionContext.getServletContext().getRealPath("/upload");
          File f=new File(path, this.fileFileName);
          os=new FileOutputStream(f);
          //读取文件
          int count=0;
          byte[] buffer=new byte[1024];
          while((count=is.read(buffer))!=-1){
              os.write(buffer, 0, count);
          }
          os.flush();
          
        } catch (Exception e) {
            
        }finally{
            if(is!=null){
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(os!=null){
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
       return null; 
   }