文件下载，可解决下载时各种异常及乱码，空格变+号（2）

			fis = new BufferedInputStream(new FileInputStream(path));
			byte[] buffer = new byte[fis.available()];
			//byte[] buffer = new byte[1024];
			fis.read(buffer);
			fis.close();
			
			response.reset();
			System.out.println("downloadName---->" + fileName);
			fileName = encodeFileName(request,fileName);
			//解决下载时，空格变加号
			fileName = StringUtils.replace(fileName, "+", "%20"); 
			response
					.addHeader("Content-Disposition", "attachment;filename="
							+ fileName);
			response.addHeader("Content-Length", "" + file.length()); // 设置返回的文件类型
			toClient = new BufferedOutputStream(response
					.getOutputStream()); // 得到向客户端输出二进制数据的对象
			toClient.write(buffer); // 输出数据
			toClient.flush();
			toClient.close();
			return fileName;
		} catch (IOException e) {
			System.out.println("----------下载文件时，输出流发生异常--------------");
			try {
				if(null != fis)
				{
					fis.close();
				}
				if(null != toClient)
				{
					toClient.close();
				}
				
			} catch (IOException e1) {
				e1.printStackTrace();
			}
			
			return fileName;
		}catch(Exception e){
			System.out.println("----------下载文件时发生异常--------------");
			return null;
		}
	}
	
	
	public static String encodeFileName(HttpServletRequest request,
			String fileName) throws UnsupportedEncodingException {
		String agent = request.getHeader("USER-AGENT");
		if (null != agent && -1 != agent.indexOf("MSIE")) {
			System.out.println("------IE浏览器下载");
			return URLEncoder.encode(fileName, "UTF8");
		} /*else if (null != agent && -1 != agent.indexOf("Mozilla")) {
			System.out.println("------火狐浏览器下载");
			return "=?UTF-8?B?"
					+ (new String(Base64.encodeBase64(fileName
							.getBytes("UTF-8")))) + "?=";
		}*/ else {
			System.out.println("------其它浏览器下载");
			//return fileName;
			return new String(fileName.getBytes(),"iso-8859-1");
		}

	}