Java 实现文件下载（Oracle中的BLOB对象）

               
               String file_id = runtime.getParameter("file_id");
		String file_name = runtime.getParameter("file_name");
		NfsFileBizDelegate fileBiz = new NfsFileBizDelegate();	

		Session sess = Session.openSession(); 

		try
		{     
                     // 替换为response.setContentType("application/x-msdownload");

      			runtime.getHttpResponse().setContentType("application/x-msdownload");

                      // response.setHeader("Content-disposition","attachment;filename="+file_name);
			runtime.getHttpResponse().setHeader("Content-disposition","attachment; filename="+file_name);

			Blob blob = fileBiz.retrieveBLOBObjectByFileId(Long.parseLong(file_id));
			if(blob!=null) {
				InputStream is = blob.getBinaryStream();
                               //  response.getOutputStream(); 
     				BufferedOutputStream bos=new java.io.BufferedOutputStream(runtime.getHttpResponse().getOutputStream());
				byte[] b  = new byte[((oracle.sql.BLOB)blob).getBufferSize()];     

				int len  =  0;     
				while((len = is.read(b)) != -1){  
					 bos.write(b,0,len); 
					 bos.flush();
				}    
				bos.close();
				is.close();
			}
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
		finally 
		{
			sess.close();
		}

  runtime 是web框架在运行中获得的，相应的替换为注释代码即可