byte[] b = new byte[1024*50];                   
 float count = 0;                   
 while((t=is.read(b))!=-1){                    
os.write(b,0,t);                    
count+=t;                    
        System.out.println(count);                   
        request.getSession().setAttribute("process", (int)(count/size)*100);                    
        System.out.println(((count/size)*100));                    }Java上传