SFTP和SSH的java实现

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 sftp与ftp

要谈sftp（SSH File Transfer Protocol），首先要谈ftp（File Transfer Protocol），大家都知道ftp是文件传输协议，它基于tcp协议，可以用来发送文件。

sftp与ssh

那sftp，就是安全(security)的ftp，因为它是基于ssh协议，ssh 为 Secure Shell 的缩写，由 IETF 的网络小组（Network Working Group）所制定；SSH 为建立在应用层基础上的安全协议。SSH 是较可靠，专为远程登录会话和其他网络服务提供安全性的协议。利用 SSH 协议可以有效防止远程管理过程中的信息泄露问题，ssh在连接和传送的过程中会加密所有的数据。所以通俗的来讲，通过ssh协议进行文件传输，那就是sftp。

那么如何使用ssh来实现文件传输呢？熟悉linux的伙伴们应该对ssh也不陌生，因为linux自带了ssh（嘘！其实我并不熟悉linux，只是知道linux自带了ssh，以前装了没多久就卸了，现在发现会linux逼格会提高不少。一定要再装一个玩一下！）。

遗憾的是，ssh基本上是基于linux和一些客户端安装软件。那么在我们平常的web开发中，要用sftp来传输文件怎么办呢？jsch就是解决办法了。

jsch简介

jsch是ssh的纯java实现。这么讲有点抽象，通俗说，你在官网上down下来就是一个jar包，引入你的项目，就可以开始使用

• 第一步：首先在maven中央仓库中查一下怎么在pom中依赖，可以点这里。
• ?

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  <!-- https://mvnrepository.com/artifact/com.jcraft/jsch -->  <dependency>     <groupId>com.jcraft</groupId>     <artifactId>jsch</artifactId>     <version>0.1.55</version> </dependency>

   

• 第二步：创建一个工具类：SFTPClient.java， 实现文件上传、下载、读取等功能：代买如下：
• ?

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  package com.zjh.logviewer.ssh;   import com.zjh.logviewer.model.FileAttri; import com.zjh.logviewer.model.Server;     import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.nio.charset.Charset; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Vector;   import org.apache.commons.lang3.ArrayUtils;   import com.jcraft.jsch.ChannelSftp; import com.jcraft.jsch.ChannelSftp.LsEntry; import com.jcraft.jsch.JSchException; import com.jcraft.jsch.SftpATTRS; import com.jcraft.jsch.SftpException;   public class SFTPClient extends BaseJchClient {       private ChannelSftp channel;       public SFTPClient(Server serverInfo) throws RemoteAccessException {         super(serverInfo);     }       private ChannelSftp openChannel() throws RemoteAccessException {         try {             if (channel != null) {                 if (channel.isConnected() || !channel.isClosed()) {                     channel.disconnect();                     channel = null;                 } else {                     return channel;                 }             }             conn();               channel = (ChannelSftp) session.openChannel("sftp");             channel.connect(DEFAULT_CONN_TIMEOUT);             return channel;           } catch (JSchException e) {             throw new RemoteAccessException(e);         }     }       /**      * 从sftp服务器下载指定文件到本地指定目录      *      * @param remoteFile 文件的绝对路径+fileName      * @param localPath 本地临时文件路径      * @return      */     public boolean download(String remoteFile, String localPath) throws RemoteAccessException {         ChannelSftp sftp = null;         try {             sftp = openChannel();             sftp.get(remoteFile, localPath);             return true;         } catch (SftpException e) {             logger.error("download remoteFile:{},localPath:{}, ex:{}", remoteFile, localPath, e);             throw new RemoteAccessException(e);         }     }       /**      * 上传文件      *      * @param directory  上传的目录-相对于SFPT设置的用户访问目录， 为空则在SFTP设置的根目录进行创建文件（除设置了服务器全磁盘访问）      * @param uploadFile 要上传的文件全路径      */     public  boolean upload(String directory, String uploadFile) throws Exception {         ChannelSftp sftp = null;         try {             try {                 sftp = openChannel();                 sftp.cd(directory); // 进入目录             } catch (SftpException sException) {                 if (sftp.SSH_FX_NO_SUCH_FILE == sException.id) { // 指定上传路径不存在                     sftp.mkdir(directory);// 创建目录                     sftp.cd(directory); // 进入目录                 }             }               File file = new File(uploadFile);             InputStream in = new FileInputStream(file);               sftp.put(in, file.getName());             in.close();         } catch (Exception e) {             throw new Exception(e.getMessage(), e);         }         return true;     }       /**      * 读取sftp上指定文件数据      *      * @param remoteFile      * @return      */     public byte[] getFile(String remoteFile) throws RemoteAccessException {         ChannelSftp sftp = null;         InputStream inputStream = null;         try {             sftp = openChannel();             inputStream = sftp.get(remoteFile);             return IOHelper.readBytes(inputStream);         } catch (SftpException | IOException e) {             logger.error("getFile remoteFile:{},ex:{}", remoteFile, e);             throw new RemoteAccessException(e);         } finally {             IOHelper.closeQuietly(inputStream);         }     }       /**      * 读取sftp上指定（文本）文件数据,并按行返回数据集合      *      * @param remoteFile      * @param charset      * @return      */     public String getFileContent(String remoteFile, Charset charset) throws RemoteAccessException {         ChannelSftp sftp = null;         InputStream inputStream = null;         try {             sftp = openChannel();             inputStream = sftp.get(remoteFile);             return IOHelper.readText(inputStream, charset);         } catch (SftpException | IOException e) {             logger.error("getFileText remoteFile:{},error:{}", remoteFile, e);             throw new RemoteAccessException(e);         } finally {             IOHelper.closeQuietly(inputStream);         }     }       /**      * 列出指定目录下文件列表      *      * @param remotePath      * @param descendant 是否递归查询子孙目录      * @param excludes 要排除的文件      * @return      */     public List<FileAttri> ls(String remotePath, boolean descendant, String... excludes) throws RemoteAccessException {         ChannelSftp sftp = null;         List<FileAttri> lsFiles;         try {             sftp = openChannel();             lsFiles = ls(sftp, remotePath, descendant, excludes);         } catch (SftpException e) {             logger.error("ls remotePath:{} , error:{}", remotePath, e.getMessage());             if ("Permission denied".equals(e.getMessage())) {                 throw new PermissionException("没有文件读取权限");             }             throw new RemoteAccessException(e);         }         if (lsFiles != null) {             Collections.sort(lsFiles);         }         return lsFiles;     }       @SuppressWarnings("unchecked")     private List<FileAttri> ls(ChannelSftp sftp, String remotePath, boolean descendant, String... excludes)             throws SftpException {         List<FileAttri> lsFiles = new ArrayList<>();         FileAttri tmpFileAttri;         long tmpSize;         String tmpFullPath;         Vector<LsEntry> vector = sftp.ls(remotePath);         for (LsEntry entry : vector) {             if (".".equals(entry.getFilename()) || "..".equals(entry.getFilename())) {                 continue;             }             tmpFullPath = UrlHelper.mergeUrl(remotePath, entry.getFilename());             if (excludes != null && ArrayUtils.contains(excludes, tmpFullPath)) {                 logger.debug("忽略目录:{}", tmpFullPath);                 continue;             }             tmpFileAttri = new FileAttri();             tmpFileAttri.setNodeName(entry.getFilename());             tmpFileAttri.setLastUpdateDate(entry.getAttrs()                     .getATime());             tmpFileAttri.setPath(tmpFullPath);               if (entry.getAttrs()                     .isDir()) {                 tmpFileAttri.setDir(true);                 if (descendant) {                     try {                         List<FileAttri> childs = ls(sftp, tmpFileAttri.getPath(), descendant, excludes);                         if (CollectionHelper.isNotEmpty(childs)) {                             tmpFileAttri.addNodes(childs);                         }                     } catch (PermissionException e) {                         tmpFileAttri.setNodeName(tmpFileAttri.getNodeName() + "[无权限]");                     }                 }             } else {                 tmpFileAttri.setDir(false);                 tmpSize = entry.getAttrs()                         .getSize();                 if (tmpSize < 1024) {                     tmpFileAttri.setSize(entry.getAttrs()                             .getSize() + "B");                 } else if (tmpSize >= 1024 && tmpSize < 1048576) {                     tmpFileAttri.setSize(MathHelper.round((entry.getAttrs()                             .getSize() / 1024f), 1) + "KB");                 } else if (tmpSize > 1048576) {                     tmpFileAttri.setSize(MathHelper.round((entry.getAttrs()                             .getSize() / 1048576f), 2) + "MB");                 }             }             lsFiles.add(tmpFileAttri);         }         return lsFiles;     }       /**      * 判断文件是否存在      *      * @param filePath      * @return      * @throws RemoteAccessException      */     public boolean isExist(String filePath) throws RemoteAccessException {         ChannelSftp sftp = null;         try {             sftp = openChannel();             SftpATTRS attrs = sftp.lstat(filePath);             return attrs != null;         } catch (SftpException e) {             logger.error("文件不存在,remotePath:{} , error:{}", filePath, e.getMessage());             return false;         }     }       @Override     public void close() throws IOException {         if (channel != null) {             try {                 channel.disconnect();             } catch (Exception e) {                 channel = null;             }         }         super.close();     } } 点击并拖拽以移动

  　　

  第三步：创建ssh交互的工具类：SSHClient.java， 实现执行单条命令、异步执行命令的功能：代码如下：huo获取

• import com.zjh.logviewer.model.Server;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.charset.StandardCharsets;
  
  import com.jcraft.jsch.ChannelExec;
  import com.jcraft.jsch.JSchException;
  
  public class SSHClient extends BaseJchClient {
  
      public SSHClient(Server serverInfo) throws RemoteAccessException {
          super(serverInfo);
      }
  
      /**
       * 执行单条命令
       * 
       * @param cmd
       * @return StringBuffer命令结果
       * @throws RemoteAccessException
       */
      public StringBuffer exec(String cmd) throws RemoteAccessException {
          String line = null;
          BufferedReader reader = null;
          ChannelExec channelExec = null;
          StringBuffer resultBuf = new StringBuffer();
          InputStream inStream = null;
          try {
              channelExec = getChannel(cmd);
              stopLastCmdThread();// 中断前一个异步命令的执行
              inStream = channelExec.getInputStream();
              channelExec.connect();
              if (inStream != null) {
                  reader = IOHelper.toBufferedReader(inStream, StandardCharsets.UTF_8.name());
                  while ((line = reader.readLine()) != null) {
                      resultBuf.append(line)
                              .append(Chars.LF);
                  }
              }
          } catch (IOException | JSchException e) {
              logger.error("执行命令异常,ip:{},cmd:{},ex:{}", serverInfo.getIp(), cmd, e);
              throw new RemoteAccessException(e);
          } finally {
              IOHelper.closeQuietly(inStream);
              if (channelExec != null) {
                  channelExec.disconnect();
              }
          }
          if (logger.isDebugEnabled()) {
              logger.debug("{}执行命令:{},结果:{}", serverInfo.getIp(), cmd, resultBuf);
          }
          return resultBuf;
      }
  
      ExecAsyncCmdThread cmdThread = null;
  
      /**
       * 异步执行命令
       * 
       * @param cmd
       * @param handler
       * @throws RemoteAccessException
       */
      public void execAsync(final String cmd, final AsyncCmdCallBack callBack) throws RemoteAccessException {
          ChannelExec channelExec = getChannel(cmd);
          stopLastCmdThread();
          cmdThread = new ExecAsyncCmdThread(channelExec, callBack);
          cmdThread.setDaemon(true);
          cmdThread.start();
      }
  
      private ChannelExec getChannel(String cmd) throws RemoteAccessException {
          conn();
          try {
              ChannelExec channel = (ChannelExec) session.openChannel("exec");
              channel.setCommand(cmd);
              channel.setInputStream(null);
              channel.setErrStream(System.err);
              return channel;
          } catch (JSchException e) {
              throw new RemoteAccessException(e);
          }
      }
  
      class ExecAsyncCmdThread extends Thread {
  
          private AsyncCmdCallBack callBack;
          private ChannelExec channelExec = null;
          private volatile boolean isRunning = false;
  
          public ExecAsyncCmdThread(final ChannelExec channelExec, AsyncCmdCallBack callBack) {
              this.channelExec = channelExec;
              this.callBack = callBack;
          }
  
          @Override
          public void run() {
              InputStream inStream = null;
              String line;
              BufferedReader reader = null;
              channelExec.setPty(true);
              try {
                  inStream = channelExec.getInputStream();
                  channelExec.connect();
                  isRunning = true;
                  reader = IOHelper.toBufferedReader(inStream, StandardCharsets.UTF_8.name());
                  while (isRunning) {
                      while ((line = reader.readLine()) != null) {
                          callBack.hanndle(line);
                      }
                      if (channelExec.isClosed()) {
                          int res = channelExec.getExitStatus();
                          isRunning = false;
                          System.out.println(String.format("Exit-status: %d,thread:%s", res, Thread.currentThread()
                                  .getId()));
                          break;
                      }
                  }
              } catch (Exception e) {
                  logger.error("", e);
              } finally {
                  IOHelper.closeQuietly(reader);
                  if (channelExec != null) {
                      channelExec.disconnect();
                  }
                  isRunning = false;
              }
          }
  
          public void close() {
              channelExec.disconnect();
              isRunning = false;
          }
  
      }
  
      void stopLastCmdThread() {
          if (cmdThread != null) {
              cmdThread.close();
          }
      }
  
      @Override
      public void close() throws IOException {
          stopLastCmdThread();
          cmdThread = null;
          super.close();
      }
  
  }

   

 第四步：在需要使用的地方，调用此两个类即可

获取项目源码

 https://github.com/BigDataAiZq/logviewer

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