springmvc框架下hdfs下载文件流直接发送httpresponse

来源：互联网发布：数据库系统的三级模式编辑：程序博客网时间：2024/06/05 05:19

1、首先是通过hdfs上的路径或者inputstream：

public InputStream downLoadFile(final String video_unique, String hdfsPath) throws IOException {FileSystem fileSystem = FileSystem.get(conf);InputStream inputStream = fileSystem.open(new Path(hdfsPath));return inputStream;}

2、然后用一个接口调用的这个方法（我自己的需求你们可以省略）：

public InputStream doVideoDownload(String video_unique) throws IOException {HDFSUtils hdfsUtils = new HDFSUtils();String hdfsPath = getVideoInfoFieldByVideoUnique(video_unique).getUpload_url() + "/" + getVideoInfoFieldByVideoUnique(video_unique).getVideo_name();InputStream inputStream = hdfsUtils.downLoadFile(video_unique, hdfsPath);return inputStream;}

3、controller访问：

    @RequestMapping(value = "/fileDownload", method = { RequestMethod.POST, RequestMethod.GET })    @ResponseBody    public Object fileDownloadDo(String video_unique, HttpServletResponse response) throws IllegalStateException, IOException {    response.setCharacterEncoding("utf-8");response.setContentType("multipart/form-data");    InputStream inputStream = null;    inputStream = iVideoCloudService.doVideoDownload(video_unique);        OutputStream os = response.getOutputStream();byte[] b = new byte[4096];int length;while ((length = inputStream.read(b)) > 0) {os.write(b, 0, length);}os.close();inputStream.close();    return null;    }

4、跟上传文件一样配置dispatchservlet，不过这里我上传文件配置了进度监听，所以是自己的类：

    <!-- SpringMVC上传文件时，为了获取上传进度，装载自定义MultipartResolver处理器 --><bean id="multipartResolver" class="com.eshore.storage.utils.CustomMultipartResolver">           <property name="maxUploadSize" value="10000000000"/>           <property name="maxInMemorySize" value="4096"/>           <property name="defaultEncoding" value="UTF-8"></property>    </bean>

5、当然，也可以吧文件读写的程序放在接口实现里，相应的controller也修改并简化：

public Object doVideoDownload(String video_unique, OutputStream outputStream) throws IOException {HDFSUtils hdfsUtils = new HDFSUtils();String hdfsPath = getVideoInfoFieldByVideoUnique(video_unique).getUpload_url() + "/" + getVideoInfoFieldByVideoUnique(video_unique).getVideo_name();InputStream inputStream = hdfsUtils.downLoadFile(video_unique, hdfsPath);byte[] b = new byte[4096];int length;while ((length = inputStream.read(b)) > 0) {outputStream.write(b, 0, length);}outputStream.close();inputStream.close();return null;}

    @RequestMapping(value = "/fileDownload", method = { RequestMethod.POST, RequestMethod.GET })    @ResponseBody    public Object fileDownloadDo(String video_unique, HttpServletResponse response) throws IllegalStateException, IOException {    response.setCharacterEncoding("utf-8");response.setContentType("multipart/form-data");        OutputStream outputStream = response.getOutputStream();    return iVideoCloudService.doVideoDownload(video_unique, outputStream);    }

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