如何使用 Java 在 SFTP 或 FTP 服务器中压缩文件？

Question

我可以在本地计算机上压缩文件，但我想通过 Java 在 SFTP 服务器中压缩 (.zip) 文件。如何传递 URL 以及如何压缩 SFTP 或 FTP 服务器中的文件？

下面是我的本地系统，我需要在 SFTP 中实现相同的功能。

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class CompressToZip {

    public static void main(String[] args) throws Exception{
        String pattern = "ddMMyyyy";
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat(pattern);
        String date = simpleDateFormat.format(new Date());
        System.out.println(date);
        String sourceFolderName =  "C:\\Users\\Desktop\\BackUpFiles\\"+date;

        File folder = new File("C:\\Users\\Desktop\\BackUpFileZip");
        String outputFileName = folder+"\\"+date+".zip";
        if(!folder.exists()){
            folder.mkdir();
        }else{
            System.out.println("Folder Exist.....");
        }


        System.currentTimeMillis();
        FileOutputStream fos = new FileOutputStream(outputFileName);
        ZipOutputStream zos = new ZipOutputStream(fos);
        //level - the compression level (0-9)
        zos.setLevel(9);

        System.out.println("Begin to compress folder : " + sourceFolderName + " to " + outputFileName);
        addFolder(zos, sourceFolderName, sourceFolderName);

        zos.close();
        System.out.println("Program ended successfully!");
    }

    private static void addFolder(ZipOutputStream zos,String folderName,String baseFolderName)throws Exception{
        File f = new File(folderName);
        if(f.exists()){

            if(f.isDirectory()){
                //Thank to peter 
                //For pointing out missing entry for empty folder
                if(!folderName.equalsIgnoreCase(baseFolderName)){
                    String entryName = folderName.substring(baseFolderName.length()+1,folderName.length()) + File.separatorChar;
                    System.out.println("Adding folder entry " + entryName);
                    ZipEntry ze= new ZipEntry(entryName);
                    zos.putNextEntry(ze);    
                }
                File f2[] = f.listFiles();
                for(int i=0;i<f2.length;i++){
                    addFolder(zos,f2[i].getAbsolutePath(),baseFolderName);    
                }
            }else{
                //add file
                //extract the relative name for entry purpose
                String entryName = folderName.substring(baseFolderName.length()+1,folderName.length());
                System.out.print("Adding file entry " + entryName + "...");
                ZipEntry ze= new ZipEntry(entryName);
                zos.putNextEntry(ze);
                FileInputStream in = new FileInputStream(folderName);
                int len;
                byte buffer[] = new byte[1024];
                while ((len = in.read(buffer)) > 0) {
                    zos.write(buffer, 0, len);
                }
                in.close();
                zos.closeEntry();
                System.out.println("OK!");

            }
        }else{
            System.out.println("File or directory not found " + folderName);
        }

    }

}

如何给出SFTP或FTP服务器地址的sourceFolderName和outputFileName？

为了连接到 SFTP，我使用以下代码：

public class JschTestDownload {

  public static void main(String s[]) {

       JSch jsch = new JSch();

       Session session = null;
       // Remote machine host name or IP
       String hostName = "xxx.xxx.xx.xxx";
       // User name to connect the remote machine
       String userName = "xxxxx";
       // Password for remote machine authentication
       String password = "xxxx";    
       // Source file path on local machine
       String srcFilePath = "/Inbound/testSFTP.txt";
       // Destination directory location on remote machine

       String destinationLocation = "C:/Users/Desktop/SftpUpDown/TestDownload";
       try {
        // Getting the session
        session = jsch.getSession(userName, hostName,22);

        // Ignore HostKeyChecking
        session.setConfig("StrictHostKeyChecking", "no");                  

        // set the password for authentication
        session.setPassword(password);
        System.out.println("try to get the connection");
        session.connect();
        System.out.println("got the connection");            
        // Getting the channel using sftp
        Channel channel = session.openChannel("sftp");
        channel.connect();
        ChannelSftp sftpChannel = (ChannelSftp) channel;

        sftpChannel.cd("/Inbound/");


        // Exist the channel
         sftpChannel.exit();

         // Disconnect the session
         session.disconnect();

       } catch (JSchException e) {
              e.printStackTrace();

       } catch (SftpException e) {
              e.printStackTrace();
       }
     }
}

通过使用上面的代码，我可以获取文件并放置文件。但我想使用第一个代码压缩 SFTP 服务器中的文件。我需要在我的计算机上运行该代码并在服务器上压缩文件并下载到我的计算机上。 我该怎么做？给我一些指导。

Answer 1

你不能。无法通过 FTP 或 SFTP 协议就地压缩文件。

您所能做的就是下载文件，在本地压缩并上传回来。你似乎能做的事情。

这并不意味着您必须（临时）将文件存储在本地。您可以使用流在内存中完成所有这些操作。

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当然，如果您对服务器有 shell 访问权限，您可以使用 SSH 协议连接并运行zip（或类似的）命令来压缩文件。但这不是 SFTP/FTP。

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