java文件下载，

java文件下载，

java中文件上传和下载是比较常用的功能，今天在项目中也有用的，就整理下拿出来分享下

1、逻辑

将文件流写入到response的流中，设置response的setContentType和addHeader为流下载即可

2、代码

@RequestMapping("FileDownLoad.do")
	@ResponseBody
	public void FileDownLoad(HttpServletRequest request, HttpServletResponse response)
			throws UnsupportedEncodingException {
		String zbGuid = request.getParameter("zbGuid");
		if(zbGuid == ""){
			return;
		}
		Object[] fileObj = FileCommonUtil.getFileByZBGUID(zbGuid, genericDao);
		String fileName = FileCommonUtil.getFileNameNoEx(((File) fileObj[0]).getName());
		File file = (File) fileObj[0];
		response.setContentType("application/x-download");
		response.addHeader("Content-Disposition", "attachment;filename=" + fileName);
		FileCommonUtil.writeFileToResponse(response, file);
	}

工具类代码

public static void writeFileToResponse(HttpServletResponse response, File file){
		OutputStream outp = null;
		FileInputStream in = null;
		try {
			outp = response.getOutputStream();
			in = new FileInputStream(file);
			byte[] b = new byte[1024];
			int i = 0;
			while ((i = in.read(b)) > 0) {
				outp.write(b, 0, i);
			}
			outp.flush();
		} catch (Exception e) {
		} finally {
			if (in != null) {
				try {
					in.close();
					in = null;
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (outp != null) {
					try {
						outp.close();
						outp = null;
					} catch (IOException e) {
						e.printStackTrace();
					}
				}
			}
		}
	}