java 下载文件

原创于 2018-08-15 13:59:21 发布 · 2k 阅读

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#java #下载

本文介绍了一个使用Java实现的文件下载方法。该方法通过输入文件路径和名称，利用HTTP响应将指定文件下载到客户端。文中详细展示了如何设置HTTP响应头、处理文件流以及异常情况。

public static void downFile(String filepath,String fileName,HttpServletResponse response) {
   FileInputStream fileinputstream = null;
   PrintWriter out = null;
   try {
   response.reset();
//     File file = new File(filepath +EmoneyConstants.MARK_SLASH+ fileName);
   File file = new File(filepath + fileName);
   if (file.exists()) {
   response.setContentType("application/x-download");// 设置response内容的类型
   response.setHeader("Content-disposition","attachment;filename="+ URLEncoder.encode(fileName, "UTF-8"));// 设置头部信息
   fileinputstream = new FileInputStream(file);
   out = response.getWriter();
   int i;
   //开始向网络传输文件流
   while ((i = fileinputstream.read()) != -1) {
   out.write(i);
   }
   } else{
   log.error("FileUtils downFile File not found!!!!");
   }
   if(out != null) out.flush();
   if(out != null) out.close();
   if(fileinputstream != null) fileinputstream.close();
   } catch (Exception e) {
   log.error("FileUtils downFile Exception " + e);
   }finally{
   try{
   if(out != null) out.close();
   if(fileinputstream != null)fileinputstream.close();
   } catch (IOException ee) {
   log.error(" download failed !! " + ee);
   }
   }
   }