Javaweb文件下载的源码，以及对应于各个浏览器的乱码的问题的解决方案

		request.setCharacterEncoding("utf-8");
		//获取文件名
		String filename=request.getParameter("filename");
		//下载文件需要相应头
		response.addHeader("content-Type","application/octet-stream");
		
		String agent=request.getHeader("User-Agent");
		if(agent.toLowerCase().indexOf("firefox")!=-1) {
			//ff防止乱码的问题  给文件名加上前缀和后缀
			response.addHeader("content-Disposition", "attachment;filename=?UTF-8?B?"+new String(Base64.encodeBase64(filename.getBytes("UTF-8")))+"?=");
		}else {
			//edge防止乱码 URLEncoder.encode(filename,"utf-8")
			response.addHeader("content-Disposition", "attachment;filename="+URLEncoder.encode(filename,"utf-8"));//filename包含了文件的后缀
		}
		
		
		
		
		//servlet通过文件地址，将文件转化为输入流，读到servlet去
		InputStream in=getServletContext().getResourceAsStream("/2580.jpg");
		
		//产生一个输出流
		ServletOutputStream out=response.getOutputStream();
		byte[] bs=new byte[10];
		int len=-1;
		while((len=in.read(bs))!=-1) {
			out.write(bs,0,len);
		}
		out.close();