Ganymed SSH-2 for Java系列7之删除远程服务器上的非空目录（方法说明）

桃扇骨 2022-08-25 10:54 143阅读 0赞

首先大家看看这段java代码的打印结果：

Vector v1 = sftpClient.ls(remoteDerectory);
    			 for (Iterator iterator2 = v1.iterator(); iterator2
    			 .hasNext();) {
    			 SFTPv3DirectoryEntry ob = (SFTPv3DirectoryEntry)
    			 iterator2.next();
    			
    			 System.out.println("--------******************----------");
    			 System.out.println("ob.longEntry is:" + ob.longEntry);
    			 System.out.println("ob.filename is:" + ob.filename);
    			 System.out.println("ob.attributes.isDirectory() is:"
    			 + ob.attributes.isDirectory());
    			 System.out.println("ob.attributes.size is:"
    			 + ob.attributes.size);
    			 System.out.println("--------******************----------");
    			 }
    			
    			 }

结果：  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
ob.longEntry is:drwxr-xr-x    3 root     root         4096 Mar  3 09:32 .  
ob.filename is:.  
ob.attributes.isDirectory() is:true  
ob.attributes.size is:4096  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
ob.longEntry is:drwxr-xr-x    3 root     root         4096 Mar  3 09:31 ..  
ob.filename is:..  
ob.attributes.isDirectory() is:true  
ob.attributes.size is:4096  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
ob.longEntry is:drwxr-xr-x    2 root     root         4096 Mar  3 09:32 t  
ob.filename is:t  
ob.attributes.isDirectory() is:true  
ob.attributes.size is:4096  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
ob.longEntry is:-rw-r--r--    1 root     root            6 Mar  3 09:31 t.txt  
ob.filename is:t.txt  
ob.attributes.isDirectory() is:false  
ob.attributes.size is:6  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------

故才有之前的方法：

List<String> filelist = new ArrayList<String>();
 
 			List<String> direlist = new ArrayList<String>();
 			direlist.add(remoteDerectory);

定义存放文件和目录的List，其存放的是全路径：

如：

fileLIst：

/usr/local/test/tt.txt

direlist：  
/usr/local/test/tt/t

列出所有目录和文件信息：

Vector v = sftpClient.ls(remoteDerectory);

遍历目录和文件信息，存入定义好的对象中：

getUrlPath(sftpClient, filelist, direlist, remoteDerectory);

逆向删除目录和文件：

System.out.println("file list is：：");
    			for (int i = filelist.size() - 1; i > -1; i--) {
    				System.out.println(filelist.get(i));
    				sftpClient.rm(filelist.get(i));
    			}
    
    			System.out.println("directory list is：：");
    			for (int i = direlist.size() - 1; i > -1; i--) {
    				System.out.println(direlist.get(i));
    				sftpClient.rmdir(direlist.get(i));
    			}

这个和之前存入list的顺序有关；

private static void getUrlPath(SFTPv3Client sftpClient,
 			List<String> filelist, List<String> direlist, String remoteDerectory)
 			throws IOException {
 
 		Vector v = sftpClient.ls(remoteDerectory);
 		for (Iterator iterator = v.iterator(); iterator.hasNext();) {
 			SFTPv3DirectoryEntry object = (SFTPv3DirectoryEntry) iterator
 					.next();
 			System.out.println(object.filename);
 			if (object.attributes.isDirectory()
 					&& object.filename.indexOf(".") == -1) {
 				String rderectory = remoteDerectory + "/" + object.filename;
 				direlist.add(rderectory);
 				getUrlPath(sftpClient, filelist, direlist, rderectory);
 
 			} else if (!object.filename.startsWith(".")
 					&& !object.filename.endsWith(".")) {
 				String path = remoteDerectory + "/" + object.filename;
 				filelist.add(path);
 			}
 		}
 
 	}

这个方法内部有个递归调用，将所有的文件和目录信息存入对应的对象中；

if (!object.filename.startsWith(".")
    					&& !object.filename.endsWith("."))

这个判断主要是排除：

\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------  
ob.longEntry is:drwxr-xr-x    3 root     root         4096 Mar  3 09:31 ..  
ob.filename is:..  
ob.attributes.isDirectory() is:true  
ob.attributes.size is:4096  
\--------\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*----------

类似这样的信息；判断不严格。

我们再看看：

Vector v = sftpClient.ls(remoteDerectory);
    for (Iterator iterator = v.iterator(); iterator.hasNext();) {
    			SFTPv3DirectoryEntry object = (SFTPv3DirectoryEntry) iterator
    					.next();

为什么Vector中存放的是

SFTPv3DirectoryEntry

这个对象，可以查看源码：

/**
    	 * List the contents of a directory.
    	 * 
    	 * @param dirName See the {@link SFTPv3Client comment} for the class for more details.
    	 * @return A Vector containing {@link SFTPv3DirectoryEntry} objects.
    	 * @throws IOException
    	 */
    	public Vector ls(String dirName) throws IOException
    	{
    		byte[] handle = openDirectory(dirName);
    		Vector result = scanDirectory(handle);
    		closeHandle(handle);
    		return result;
    	}

继续查看：

Vector result = scanDirectory(handle); 
 
 
 
 
 
 private final Vector scanDirectory(byte[] handle) throws IOException
 	{
 		Vector files = new Vector();
 
 		while (true)
 		{
 			int req_id = generateNextRequestID();
 
 			TypesWriter tw = new TypesWriter();
 			tw.writeString(handle, 0, handle.length);
 
 			if (debug != null)
 			{
 				debug.println("Sending SSH_FXP_READDIR...");
 				debug.flush();
 			}
 
 			sendMessage(Packet.SSH_FXP_READDIR, req_id, tw.getBytes());
 
 			byte[] resp = receiveMessage(34000);
 
 			if (debug != null)
 			{
 				debug.println("Got REPLY.");
 				debug.flush();
 			}
 
 			TypesReader tr = new TypesReader(resp);
 
 			int t = tr.readByte();
 
 			int rep_id = tr.readUINT32();
 			if (rep_id != req_id)
 				throw new IOException("The server sent an invalid id field.");
 
 			if (t == Packet.SSH_FXP_NAME)
 			{
 				int count = tr.readUINT32();
 
 				if (debug != null)
 					debug.println("Parsing " + count + " name entries...");
 
 				while (count > 0)
 				{
 					SFTPv3DirectoryEntry dirEnt = new SFTPv3DirectoryEntry();
 
 					dirEnt.filename = tr.readString(charsetName);
 					dirEnt.longEntry = tr.readString(charsetName);
 
 					dirEnt.attributes = readAttrs(tr);
 					files.addElement(dirEnt);
 
 					if (debug != null)
 						debug.println("File: '" + dirEnt.filename + "'");
 					count--;
 				}
 				continue;
 			}
 
 			if (t != Packet.SSH_FXP_STATUS)
 				throw new IOException("The SFTP server sent an unexpected packet type (" + t + ")");
 
 			int errorCode = tr.readUINT32();
 
 			if (errorCode == ErrorCodes.SSH_FX_EOF)
 				return files;
 
 			throw new SFTPException(tr.readString(), errorCode);
 		}
 	}
 
 首先定义了：
 Vector files = new Vector();
 
 最后存放的是： 
 files.addElement(dirEnt);
 
 
 在看看：SFTPv3DirectoryEntry对象定义：
 public class SFTPv3DirectoryEntry
 {
 	/**
 	 * A relative name within the directory, without any path components.
 	 */
 	public String filename;
 
 	/**
 	 * An expanded format for the file name, similar to what is returned by
 	 * "ls -l" on Un*x systems.
 	 * 
 	 * The format of this field is unspecified by the SFTP v3 protocol.
 	 * It MUST be suitable for use in the output of a directory listing
 	 * command (in fact, the recommended operation for a directory listing
 	 * command is to simply display this data). However, clients SHOULD NOT
 	 * attempt to parse the longname field for file attributes; they SHOULD
 	 * use the attrs field instead.
 	 * 
 	 * The recommended format for the longname field is as follows: 
 	 * <code>-rwxr-xr-x 1 mjos staff 348911 Mar 25 14:29 t-filexfer</code>
 	 */
 	public String longEntry;
 
 	/**
 	 * The attributes of this entry.
 	 */
 	public SFTPv3FileAttributes attributes;
 
 其包含了三个基本属性，分别是： 
 filename 文件或者目录名称；
 
 
 longEntry  目录（d）权限等基本信息：例如：drwxr-xr-x    2 root     root         4096 Mar  3 09:32 t 或者 -rw-r--r--    1 root     root            3 Mar  3 09:31 tt.txt
 
 
 SFTPv3FileAttributes 定义了entry 属性对象，存放是否是目录，权限等基础信息；
 
 
 
 
 
 继续查看源码：
 
 
 public class SFTPv3FileAttributes
 {
 	/**
 	 * The SIZE attribute. <code>NULL</code> if not present.
 	 */
 	public Long size = null;
 
 	/**
 	 * The UID attribute. <code>NULL</code> if not present.
 	 */
 	public Integer uid = null;
 
 	/**
 	 * The GID attribute. <code>NULL</code> if not present.
 	 */
 	public Integer gid = null;
 
 	/**
 	 * The POSIX permissions. <code>NULL</code> if not present.
 	 * 
 	 * Here is a list:
 	 * 
 	 * <pre>Note: these numbers are all OCTAL.
 	 * 
 	 * S_IFMT 0170000 bitmask for the file type bitfields
 	 * S_IFSOCK 0140000 socket
 	 * S_IFLNK 0120000 symbolic link
 	 * S_IFREG 0100000 regular file
 	 * S_IFBLK 0060000 block device
 	 * S_IFDIR 0040000 directory
 	 * S_IFCHR 0020000 character device
 	 * S_IFIFO 0010000 fifo 
 	 * S_ISUID 0004000 set UID bit
 	 * S_ISGID 0002000 set GID bit 
 	 * S_ISVTX 0001000 sticky bit
 	 * 
 	 * S_IRWXU 00700 mask for file owner permissions
 	 * S_IRUSR 00400 owner has read permission
 	 * S_IWUSR 00200 owner has write permission
 	 * S_IXUSR 00100 owner has execute permission
 	 * S_IRWXG 00070 mask for group permissions
 	 * S_IRGRP 00040 group has read permission
 	 * S_IWGRP 00020 group has write permission
 	 * S_IXGRP 00010 group has execute permission
 	 * S_IRWXO 00007 mask for permissions for others (not in group)
 	 * S_IROTH 00004 others have read permission
 	 * S_IWOTH 00002 others have write permisson
 	 * S_IXOTH 00001 others have execute permission
 	 * </pre>
 	 */
 	public Integer permissions = null;
 
 	/**
 	 * The ATIME attribute. Represented as seconds from Jan 1, 1970 in UTC.
 	 * <code>NULL</code> if not present.
 	 */
 	public Integer atime = null;
 
 	/**
 	 * The MTIME attribute. Represented as seconds from Jan 1, 1970 in UTC.
 	 * <code>NULL</code> if not present.
 	 */
 	public Integer mtime = null;
 
 	/**
 	 * Checks if this entry is a directory.
 	 * 
 	 * @return Returns true if permissions are available and they indicate
 	 * that this entry represents a directory.
 	 */
 	public boolean isDirectory()
 	{
 		if (permissions == null)
 			return false;
 		
 		return ((permissions.intValue() & 0040000) != 0);
 	}
 	
 	/**
 	 * Checks if this entry is a regular file.
 	 * 
 	 * @return Returns true if permissions are available and they indicate
 	 * that this entry represents a regular file.
 	 */
 	public boolean isRegularFile()
 	{
 		if (permissions == null)
 			return false;
 		
 		return ((permissions.intValue() & 0100000) != 0);
 	}
 	
 	/**
 	 * Checks if this entry is a a symlink.
 	 * 
 	 * @return Returns true if permissions are available and they indicate
 	 * that this entry represents a symlink.
 	 */
 	public boolean isSymlink()
 	{
 		if (permissions == null)
 			return false;
 		
 		return ((permissions.intValue() & 0120000) != 0);
 	}
 	
 	/**
 	 * Turn the POSIX permissions into a 7 digit octal representation.
 	 * Note: the returned value is first masked with <code>0177777</code>.
 	 * 
 	 * @return <code>NULL</code> if permissions are not available.
 	 */
 	public String getOctalPermissions()
 	{
 		if (permissions == null)
 			return null;
 
 		String res = Integer.toString(permissions.intValue() & 0177777, 8);
 
 		StringBuffer sb = new StringBuffer();
 
 		int leadingZeros = 7 - res.length();
 
 		while (leadingZeros > 0)
 		{
 			sb.append('0');
 			leadingZeros--;
 		}
 
 		sb.append(res);
 
 		return sb.toString();
 	}
 }
 
 这个里面基本定义了权限，是否是目录等基本信息；