Selenium断言文件是否下载成功

项目中，存在点击后下载的业务流程，而selenium本身没有很好的方法去断言文件是否下载成功。此时我们可以通过WatchService去监听目录文件，来确定文件是否下载成功。

//监听所下载的文件名
        public static String getDownloadedDocumentName(String filepath, String filename)
        {    
            String downloadedFileName = null;
            boolean valid = true;
            boolean found = false;
            //default timeout in seconds
            long timeOut = 30; 
            try 
            {                    
                Path downloadFolderPath = Paths.get(filepath);
                WatchService watchService = FileSystems.getDefault().newWatchService();
                downloadFolderPath.register(watchService, StandardWatchEventKinds.ENTRY_CREATE);
                long startTime = System.currentTimeMillis();
                do 
                {
                    WatchKey watchKey;
                    watchKey = watchService.poll(timeOut,TimeUnit.SECONDS);
                    long currentTime = (System.currentTimeMillis()-startTime)/1000;
                    if(currentTime>timeOut)
                    {
                        System.out.println("Download operation timed out.. Expected file was not downloaded");
                        return downloadedFileName;
                    }
                    
                    for (WatchEvent<?> event: watchKey.pollEvents())
                    {
                        WatchEvent.Kind<?> kind = event.kind(); 
                        if (kind.equals(StandardWatchEventKinds.ENTRY_CREATE)) 
                        {
                            String fileName = event.context().toString();
                            System.out.println("New File Created:" + fileName);
                            if(fileName.endsWith(filename))
                            {
                                downloadedFileName = fileName;
                                System.out.println("Downloaded file found with extension " + filename + ". File name is " + fileName);
                                Thread.sleep(500);
                                found = true;
                                break;
                            }
                        }
                    }
                    if(found)
                    {
                        return downloadedFileName;
                    }
                    else
                    {
                        currentTime = (System.currentTimeMillis()-startTime)/1000;
                        if(currentTime>timeOut)
                        {
                            System.out.println("Failed to download expected file");
                            return downloadedFileName;
                        }
                        valid = watchKey.reset();
                    }
                } while (valid);
            } 
            
            catch (InterruptedException e) 
            {
                System.out.println("Interrupted error - " + e.getMessage());
                e.printStackTrace();
            }
            catch (NullPointerException e) 
            {
                System.out.println("Download operation timed out.. Expected file was not downloaded");
            }
            catch (Exception e)
            {
                System.out.println("Error occured - " + e.getMessage());
                e.printStackTrace();
            }
            return downloadedFileName;
    }

确认文件是否下载完成

/确认文件下载是否完成
        public static Boolean isFileDownloaded_Ext(String filepath, String filename) {
            boolean flag=false;
            File dir = new File(filepath);
            File[] files = dir.listFiles();
            if (files == null || files.length == 0) {
                flag = false;
            }
            
            for (int i = 0; i <files.length; i++) {
                if(files[i].getName().contains(filename)) {
                    flag=true;
                }
            }
            return flag;
        }

通过上面的方法即可得到下载后的文件名，然后通过下载的文件和用例中的预期做断言即可