我不知道如何模擬我將文件所有者從行Path path = newFile.toPath();更改到末尾的部分。這是我的功能：@RequestMapping(value = "/upload", method = RequestMethod.POST)    @ResponseBody    public String uploadEndpoint(@RequestParam("file") MultipartFile file,                                 @RequestParam("usernameSession") String usernameSession,                                 @RequestHeader("current-folder") String folder) throws IOException {        String[] pathArray = file.getOriginalFilename().split("[\\\\\\/]");        String originalName = pathArray[pathArray.length-1];        LOGGER.info("Upload triggerred with : {} , filename : {}", originalName, file.getName());        String workingDir = URLDecoder.decode(folder.replace("!", "."),                StandardCharsets.UTF_8.name())                .replace("|", File.separator);        LOGGER.info("The file will be moved to : {}", workingDir);        File newFile = new File(workingDir + File.separator + originalName);        //UserPrincipal owner = Files.getOwner(newFile.toPath());        file.transferTo(newFile);        Path path = newFile.toPath();        FileOwnerAttributeView foav = Files.getFileAttributeView(path, FileOwnerAttributeView.class);        UserPrincipal owner = foav.getOwner();        System.out.format("Original owner  of  %s  is %s%n", path, owner.getName());    }這是測試：@Test    public void uploadEndpointTest() throws Exception {        PowerMockito.whenNew(File.class).withAnyArguments().thenReturn(file);        Mockito.when(multipartFile.getOriginalFilename()).thenReturn("src/test/resources/download/test.txt");        assertEquals("ok", fileExplorerController.uploadEndpoint(multipartFile, "userName", "src/test/resources/download"));    }我遇到了一個例外，因為“userName”不是用戶。我想模擬它在 Windows 用戶中尋找匹配項的調用。當我設置我的窗口的用戶名而不是“userName”時它可以工作，但我不能讓我的窗口的用戶名。我試圖嘲笑fs.getUserPrincipalLookupService()；但upls.lookupPrincipalByName(usernameSession);我不知道要返回什么來模擬通話。