ssm展示HDFS文件列表，上传文件，删除文件，下载文件前后代码

1. 展示HDFS文件列表

Controller层代码：

@Controller
@RequestMapping("/hdfs")
public class HDFSController {
    
    @Autowired
    private HdfsService hdfsService;

    // 展示HDFS文件列表
    @RequestMapping("/list")
    public String list(Model model) throws Exception {
        List<String> fileList = hdfsService.listFiles("/");
        model.addAttribute("fileList", fileList);
        return "hdfs/list";
    }
    
    // ...
}

Service层代码：

@Service
public class HdfsServiceImpl implements HdfsService {

    @Autowired
    private FileSystem fileSystem;

    // 列出HDFS文件列表
    @Override
    public List<String> listFiles(String path) throws Exception {
        List<String> fileList = new ArrayList<>();
        RemoteIterator<LocatedFileStatus> files = fileSystem.listFiles(new Path(path), true);
        while (files.hasNext()) {
            LocatedFileStatus file = files.next();
            fileList.add(file.getPath().toString());
        }
        return fileList;
    }
    
    // ...
}

2. 上传文件

Controller层代码：

@Controller
@RequestMapping("/hdfs")
public class HDFSController {
    
    @Autowired
    private HdfsService hdfsService;

    // 上传文件
    @PostMapping("/upload")
    public String upload(@RequestParam("file") MultipartFile file, RedirectAttributes redirectAttributes) throws Exception {
        if (file.isEmpty()) {
            redirectAttributes.addFlashAttribute("message", "Please select a file to upload");
            return "redirect:/hdfs/list";
        }
        String fileName = file.getOriginalFilename();
        byte[] bytes = file.getBytes();
        hdfsService.uploadFile(bytes, "/" + fileName);
        redirectAttributes.addFlashAttribute("message", "You successfully uploaded '" + fileName + "'");
        return "redirect:/hdfs/list";
    }
    
    // ...
}

Service层代码：

@Service
public class HdfsServiceImpl implements HdfsService {

    @Autowired
    private FileSystem fileSystem;

    // 上传文件
    @Override
    public void uploadFile(byte[] bytes, String path) throws Exception {
        FSDataOutputStream outputStream = fileSystem.create(new Path(path));
        outputStream.write(bytes);
        outputStream.flush();
        outputStream.close();
    }
    
    // ...
}

3. 删除文件

Controller层代码：

@Controller
@RequestMapping("/hdfs")
public class HDFSController {
    
    @Autowired
    private HdfsService hdfsService;

    // 删除文件
    @GetMapping("/delete")
    public String delete(@RequestParam("path") String path, RedirectAttributes redirectAttributes) throws Exception {
        hdfsService.deleteFile(path);
        redirectAttributes.addFlashAttribute("message", "You successfully deleted '" + path + "'");
        return "redirect:/hdfs/list";
    }
    
    // ...
}

Service层代码：

@Service
public class HdfsServiceImpl implements HdfsService {

    @Autowired
    private FileSystem fileSystem;

    // 删除文件
    @Override
    public void deleteFile(String path) throws Exception {
        fileSystem.delete(new Path(path), true);
    }
    
    // ...
}

4. 下载文件

Controller层代码：

@Controller
@RequestMapping("/hdfs")
public class HDFSController {
    
    @Autowired
    private HdfsService hdfsService;

    // 下载文件
    @GetMapping("/download")
    public ResponseEntity<byte[]> download(@RequestParam("path") String path) throws Exception {
        byte[] bytes = hdfsService.downloadFile(path);
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentDispositionFormData("attachment", new File(path).getName());
        headers.setContentLength(bytes.length);
        return new ResponseEntity<>(bytes, headers, HttpStatus.OK);
    }
    
    // ...
}

Service层代码：

@Service
public class HdfsServiceImpl implements HdfsService {

    @Autowired
    private FileSystem fileSystem;

    // 下载文件
    @Override
    public byte[] downloadFile(String path) throws Exception {
        FSDataInputStream inputStream = fileSystem.open(new Path(path));
        byte[] bytes = IOUtils.toByteArray(inputStream);
        inputStream.close();
        return bytes;
    }
    
    // ...
}