Java上传下载功能的实现

??<form?action="xxoo.do"?enctype="multipart/form-data"?method="post">
	<input?type="file"?name="file"?/>
	?<button?type="submit"?class="btn?btn-primary">?提交
??</form>

?enctype="multipart/form-data"?method="post"

public?void?downLoad(String?newFileName){
	InputStream?is?=?null;
	OutputStream?os?=?null;
	HttpServletResponse?response?=?ServletActionContext.getResponse();
	try{
		String?contentType="application/octet-stream";??
		response.setContentType(contentType);??
		response.setHeader("Content-disposition","attachment;filename=""+newFileName+""");
		is=new?BufferedInputStream(new?FileInputStream(newFileName));??		?
		ByteArrayOutputStream?baos=new?ByteArrayOutputStream();??
		os=new?BufferedOutputStream(response.getOutputStream());??	??
		byte[]?buffer=new?byte[4*1024];???
		int?read=0;????
		while((read=is.read(buffer))!=-1){??
		????baos.write(buffer,read);??
		}??
		os.write(baos.toByteArray());??
		}catch(Exception?e){
			e.printStackTrace();
		}finally{
			closeStream(os,?is);
		}
		
	}