問題描述

我一直在使用 JakartaFtpWrapper 將文件從客戶端 Java 應用程序上傳到我的服務器(用于備份目的).

I've been using JakartaFtpWrapper to upload files from the client Java application to my server (for backup purposes).

上傳的文件有文本文件、png文件和jpgs.

The files that are uploaded are text files, png files and jpgs.

我注意到在本地機器上有效的 jpg 文件在服務器(它們被 FTP 傳輸到的位置)上不知何故變得不可讀(損壞的文件).圖像文件大小與原始文件大小相似，但不知何故存在缺陷.

I've noticed that the jpg files which are valid on the local machine - somehow become unreadable (corrupt files) on the server (where they were FTPd to). The image file size is similar to the original one, but somehow it is defected.

這是我用來將 jpg 寫入本地磁盤的代碼:

Here's a code I'm using to write the jpg to the LOCAL disk:

public static void writeJpeg(BufferedImage bfImg, String fileName, float quality) throws IOException{
FileImageOutputStream output = null;
try{
    Iterator iter = ImageIO.getImageWritersByFormatName("jpeg");
    ImageWriter writer = (ImageWriter)iter.next();
    ImageWriteParam iwp = writer.getDefaultWriteParam();
    iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
    iwp.setCompressionQuality(quality);   // an integer between 0 and 1     
    File file = new File(fileName);
    output = new FileImageOutputStream(file);
    writer.setOutput(output);
    IIOImage image = new IIOImage(bfImg, null, null);
    writer.write(null, image, iwp);
}
finally{
    if (output != null){
        output.close();
    }
}

ftp 代碼很簡單:

JakartaFtpWrapper ftpClient = new JakartaFtpWrapper();
ftpClient.connectAndLogin(FTP_URL, FTP_USER, FTP_PASSWORD);
ftpClient.setPassiveMode(true);

File[] imageFiles = folder.listFiles()


  for (int j=0; j<imageFiles.length; j++){
        File imageFile = imageFiles[j];
        if (imageFile != null && imageFile.isFile() && (FileUtils.getFileSuffix(imageFile).equals("jpg") || FileUtils.getFileSuffix(imageFile).equals("png"))){ // upload only image files
            ftpClient.uploadFile(imageFile.getAbsolutePath(), imageFile.getName());
        }
    }

謝謝，然

推薦答案

服務器上正在運行什么?它是開箱即用"的 FTP 服務器還是您編寫的?

What's running on the server? Is it an "out of the box" FTP server or something you wrote?

圖像是二進制數據.如果 JakartaFtpWrapper 提供了一些將 FTP 傳輸設置為二進制模式的選項，那么您應該這樣做；我認為您的問題最可能的原因是在文本模式下處理傳輸的默認嘗試錯誤.如果您按字節比較小圖像，您應該會看到在 0x0a 旁邊添加或刪除了回車 ((char) 0x0d == (char) 13).如果是這樣，那是你的問題.

Images are binary data. If JakartaFtpWrapper offers some option of putting the FTP transfer into binary mode, you should do that; I think the most likely cause of your problem is a bad default attempt to process the transfer in text mode. If you compare small images bytewise, you should see Carriage Returns ((char) 0x0d == (char) 13) being added or removed next to 0x0a's. If so, that's your problem.

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