SpringBoot Hadoop HDFS目錄文件下載

    @RequestMapping(value = "/downDir", method = {RequestMethod.POST, RequestMethod.GET})
    public ResponseEntity<byte[]> downDir(@RequestParam("dirPath") String dirPath, HttpServletRequest request) throws Exception {
        HttpHeaders headers = new HttpHeaders();
        headers.add("Cache-Control", "no-cache, no-store, must-revalidate");
		// 指定返回的zip文件名，這裏就直接用時間戳了，可以自己選擇
        headers.add("Content-Disposition", "attachment; filename=" + System.currentTimeMillis() + ".zip");
        headers.add("Pragma", "no-cache");
        headers.add("Expires", "0");
        headers.add("Last-Modified", new Date().toString());
        headers.add("ETag", String.valueOf(System.currentTimeMillis()));
        ByteArrayOutputStream zos = downloadDirectory(dirPath);
        byte[] out = zos.toByteArray();
        zos.close();
        ResponseEntity<byte[]> response = new ResponseEntity<>(out, headers, HttpStatus.OK);
        return response;

    }

	//壓縮目錄
    public void compress(String dirPath, ZipOutputStream zipOutputStream, FileSystem fs) throws IOException {
		// 要下載的目錄dirPath
        FileStatus[] fileStatulist = fs.listStatus(new Path(dirPath));
        for (int i = 0; i < fileStatulist.length; i++) {
			String fileName = fileStatulist[i].getPath().getName();
            if (fileStatulist[i].isFile()) {
                Path path = fileStatulist[i].getPath();
                FSDataInputStream inputStream = fs.open(path);
                zipOutputStream.putNextEntry(new ZipEntry(fileName));
                IOUtils.copyBytes(inputStream, zipOutputStream, 1024);
                inputStream.close();
            } else {
                zipOutputStream.putNextEntry(new ZipEntry(fileName+ "/"));//因爲是目錄，所以加上/ 就會自動分層
                // 這裏的substring是因爲這個返回的是hdfs://192.168.1.100:9000XXXXX/xxx/xx一大堆，
				// 而我們要的是/data/img類似這樣的目錄。
				compress(fileStatulist[i].getPath().toString().substring(25), zipOutputStream, fs);
            }
        }
    }
	//下載一個目錄
    public ByteArrayOutputStream downloadDirectory(String dirPath) throws IOException, InterruptedException, URISyntaxException {

        Configuration conf = new Configuration();
        FileSystem fs = FileSystem.get(new URI("hdfs://192.168.1.100:9000"), conf, "hadoop");
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        ZipOutputStream zos = new ZipOutputStream(out);
        compress(dirPath, zos, fs);
        zos.close();
        return out;
    }

其中還遇到一些問題，由於流沒有關閉，導致下載的zip文件解壓的時候是損壞的。所以流記得關很重要。

參考
https://blog.csdn.net/u010366748/article/details/78615004
https://blog.csdn.net/qq_33872191/article/details/84977588
https://blog.csdn.net/liu16659/article/details/79200775
https://www.cnblogs.com/walker-/p/9768834.html
https://blog.csdn.net/qq_41848006/article/details/85786908