JSch 远程连接服务器

2024-08-04 03 SpringBoot JSch 0 评论阅读时长: 17(分)

1. JSch介绍

JSch 是SSH2的纯Java实现。JSch允许连接到sshd的服务器并使用端口转发、X11转发、文件传输等，并且可以将其功能集成到自己的Java程序中。

2. 实现原理

根据远程主机的IP地址、用户名和密码，建立会话session

设置用户信息(包括密码和Userinfo)，然后连接session，getSession()只是创建一个session，需要设置必要的认证信息之后，调用connect()才能建立连接

设置channel上需要远程执行的shell脚本，连接channel,就可以远程执行该shell脚本，调用openChannel(String type)可以在session上打开指定类型的channel。该channel只是被初始化，使用前需要先调用connect()进行连接

可以读取远程执行shell脚本的输出，然后依次断开channel和session的连接

3. 代码工程

实现文件上传到服务器，服务器下载文件以及执行服务器命令

引入pom

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>JSchDemo</artifactId>
  <version>1.0</version>

  <name>JSchDemo</name>
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
      <version>2.4.5</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-autoconfigure</artifactId>
      <version>2.4.5</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
      <version>2.4.5</version>
    </dependency>
    <dependency>
      <groupId>com.jcraft</groupId>
      <artifactId>jsch</artifactId>
      <version>0.1.55</version>
    </dependency>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.24</version>
    </dependency>
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.78</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

Remote实体类

@Data
public class Remote {

    private String host;
    private final int port = 22;
    private String user;
    private String password;
    private final String identity = "~/.ssh/id_rsa";
    private String passphrase;
}

JschUtils工具类

package org.example;

import com.jcraft.jsch.*;
import lombok.extern.slf4j.Slf4j;

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;

/**
 * @author xiaoyuge
 */
@Slf4j
public class JschUtils {

    public static final int SESSION_TIMEOUT = 30000;
    public static final int CONNECT_TIMEOUT = 3000;

    public static Session getSession(Remote remote) throws JSchException {
        JSch jSch = new JSch();
        if (Files.exists(Paths.get(remote.getIdentity()))) {
            jSch.addIdentity(remote.getIdentity(), remote.getPassphrase());
        }
        Session session = jSch.getSession(remote.getUser(), remote.getHost(), remote.getPort());
        session.setPassword(remote.getPassword());
        session.setConfig("StrictHostKeyChecking", "no");
        return session;
    }

    public static List<String> remoteExecute(Session session, String command) throws JSchException {
        log.debug(">> {}", command);
        List<String> resultLines = new ArrayList<>();
        ChannelExec channel = null;
        try {
            channel = openExecChannel(session);
            channel.setCommand(command);
            InputStream input = channel.getInputStream();
            channel.connect(CONNECT_TIMEOUT);
            try {
                BufferedReader inputReader = new BufferedReader(new InputStreamReader(input));
                String inputLine;
                while ((inputLine = inputReader.readLine()) != null) {
                    log.debug("   {}", inputLine);
                    resultLines.add(inputLine);
                }
            } finally {
                if (input != null) {
                    try {
                        input.close();
                    } catch (Exception e) {
                        log.error("JSch inputStream close error:", e);
                    }
                }
            }
        } catch (IOException e) {
            log.error("IOException:", e);
        } finally {
            disconnect(channel);
        }
        return resultLines;
    }

    /**
     * scp file to remote server
     *
     * @param session     session
     * @param source      local file
     * @param destination remote target file
     * @return file size
     */
    public static long scpTo(Session session, String source, String destination) {
        FileInputStream fileInputStream = null;
        ChannelExec channel = null;
        try {
            channel = openExecChannel(session);
            OutputStream out = channel.getOutputStream();
            InputStream in = channel.getInputStream();
            boolean ptimestamp = false;
            String command = "scp";
            if (ptimestamp) {
                command += " -p";
            }
            command += " -t " + destination;
            channel.setCommand(command);
            channel.connect(CONNECT_TIMEOUT);
            if (checkAck(in) != 0) {
                return -1;
            }
            File _lfile = new File(source);
            if (ptimestamp) {
                command = "T " + (_lfile.lastModified() / 1000) + " 0";
                // The access time should be sent here,
                // but it is not accessible with JavaAPI ;-<
                command += (" " + (_lfile.lastModified() / 1000) + " 0\n");
                out.write(command.getBytes());
                out.flush();
                if (checkAck(in) != 0) {
                    return -1;
                }
            }
            //send "C0644 filesize filename", where filename should not include '/'
            long fileSize = _lfile.length();
            command = "C0644 " + fileSize + " ";
            if (source.lastIndexOf('/') > 0) {
                command += source.substring(source.lastIndexOf('/') + 1);
            } else {
                command += source;
            }
            command += "\n";
            out.write(command.getBytes());
            out.flush();
            if (checkAck(in) != 0) {
                return -1;
            }
            //send content of file
            fileInputStream = new FileInputStream(source);
            byte[] buf = new byte[1024];
            long sum = 0;
            while (true) {
                int len = fileInputStream.read(buf, 0, buf.length);
                if (len <= 0) {
                    break;
                }
                out.write(buf, 0, len);
                sum += len;
            }
            //send '\0'
            buf[0] = 0;
            out.write(buf, 0, 1);
            out.flush();
            if (checkAck(in) != 0) {
                return -1;
            }
            return sum;
        } catch (JSchException e) {
            log.error("scp to caught jsch exception, ", e);
        } catch (IOException e) {
            log.error("scp to caught io exception, ", e);
        } catch (Exception e) {
            log.error("scp to error, ", e);
        } finally {
            closeInputStream(fileInputStream);
            disconnect(channel);
        }
        return -1;
    }

    /**
     * scp remote file to local
     *
     * @param session     session
     * @param source      remote file
     * @param destination local file
     * @return file size
     */
    public static long scpFrom(Session session, String source, String destination) {
        FileOutputStream fileOutputStream = null;
        ChannelExec channel = null;
        try {
            channel = openExecChannel(session);
            channel.setCommand("scp -f " + source);
            OutputStream out = channel.getOutputStream();
            InputStream in = channel.getInputStream();
            channel.connect();
            byte[] buf = new byte[1024];
            //send '\0'
            buf[0] = 0;
            out.write(buf, 0, 1);
            out.flush();
            while (true) {
                if (checkAck(in) != 'C') {
                    break;
                }
            }
            //read '644 '
            in.read(buf, 0, 4);
            long fileSize = 0;
            while (true) {
                if (in.read(buf, 0, 1) < 0) {
                    break;
                }
                if (buf[0] == ' ') {
                    break;
                }
                fileSize = fileSize * 10L + (long) (buf[0] - '0');
            }
            String file = null;
            for (int i = 0; ; i++) {
                in.read(buf, i, 1);
                if (buf[i] == (byte) 0x0a) {
                    file = new String(buf, 0, i);
                    break;
                }
            }
            // send '\0'
            buf[0] = 0;
            out.write(buf, 0, 1);
            out.flush();
            // read a content of lfile
            if (Files.isDirectory(Paths.get(destination))) {
                fileOutputStream = new FileOutputStream(destination + File.separator + file);
            } else {
                fileOutputStream = new FileOutputStream(destination);
            }
            long sum = 0;
            while (true) {
                int len = in.read(buf, 0, buf.length);
                if (len <= 0) {
                    break;
                }
                sum += len;
                if (len >= fileSize) {
                    fileOutputStream.write(buf, 0, (int) fileSize);
                    break;
                }
                fileOutputStream.write(buf, 0, len);
                fileSize -= len;
            }
            return sum;
        } catch (JSchException e) {
            log.error("scp to caught jsch exception, ", e);
        } catch (IOException e) {
            log.error("scp to caught io exception, ", e);
        } catch (Exception e) {
            log.error("scp to error, ", e);
        } finally {
            closeOutputStream(fileOutputStream);
            disconnect(channel);
        }
        return -1;
    }

    /**
     * remote edit
     *
     * @param session session
     * @param source  target file
     * @param process edit command collect
     * @return isSuccess
     */
    private static boolean remoteEdit(Session session, String source, Function<List<String>, List<String>> process) {
        InputStream in = null;
        OutputStream out = null;
        try {
            String fileName = source;
            int index = source.lastIndexOf('/');
            if (index >= 0) {
                fileName = source.substring(index + 1);
            }
            //backup source
            remoteExecute(session, String.format("cp %s %s", source, source + ".bak." + System.currentTimeMillis()));
            //scp from remote
            String tmpSource = System.getProperty("java.io.tmpdir") + session.getHost() + "-" + fileName;
            scpFrom(session, source, tmpSource);
            in = new FileInputStream(tmpSource);
            //edit file according function process
            String tmpDestination = tmpSource + ".des";
            out = new FileOutputStream(tmpDestination);
            List<String> inputLines = new ArrayList<>();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            String inputLine = null;
            while ((inputLine = reader.readLine()) != null) {
                inputLines.add(inputLine);
            }
            List<String> outputLines = process.apply(inputLines);
            for (String outputLine : outputLines) {
                out.write((outputLine + "\n").getBytes());
                out.flush();
            }
            //scp to remote
            scpTo(session, tmpDestination, source);
            return true;
        } catch (Exception e) {
            log.error("remote edit error, ", e);
            return false;
        } finally {
            closeInputStream(in);
            closeOutputStream(out);
        }
    }

    /**
     * update file
     *
     * @param session   session
     * @param in        file stream
     * @param directory local dir
     * @param fileName  FTP server file name：xxx.txt ||xxx.txt.zip
     */
    public static boolean uploadFile(Session session, InputStream in, String directory, String fileName) {
        log.info(">>>>>>>>uploadFile--ftp start>>>>>>>>>>>>>");
        ChannelSftp channel = null;
        try {
            channel = openSftpChannel(session);
            channel.connect(CONNECT_TIMEOUT);
            String[] folders = directory.split("/");
            try {
                for (int i = 0; i < folders.length; i++) {
                    if (i == 0 && folders[i].length() == 0) {
                        channel.cd("/");
                    } else if (folders[i].length() > 0) {
                        try {
                            channel.cd(folders[i]);
                        } catch (SftpException e) {
                            channel.mkdir(folders[i]);
                            channel.cd(folders[i]);
                        }
                    }
                }
            } catch (SftpException e) {
                log.error("ftp create file fail" + directory, e);
                return false;
            }

            try {
                channel.put(in, fileName);
            } catch (SftpException e) {
                log.error("sftp error-->" + e.getMessage(), e);
                return false;
            }

            log.info(">>>>>>>>uploadFile--ftp upload end>>>>>>>>>>>>>");
            log.info(">>>>>>>>ftp upload dir：{}，filename：{}>>>>>>>>>>>>>", directory, fileName);

            return true;
        } catch (JSchException e) {
            log.error("JSch error-->" + e.getMessage(), e);
            return false;
        } finally {
            closeInputStream(in);
            disconnect(channel);
        }
    }


    /**
     * @param channel   sftp connect
     * @param directory
     * @param fileName
     * @return
     */
    public static InputStream stream(ChannelSftp channel, String directory, String fileName) {
        try {
            channel.connect(CONNECT_TIMEOUT);
            InputStream inputStream = channel.get(directory + "/" + fileName);
            log.info(">>>>>>>>ftp file directory：{}，filename：{}>>>>>>>>>>>>>", directory, fileName);
            return inputStream;
        } catch (SftpException e) {
            log.error("sftp error-->" + e.getMessage());
            return null;
        } catch (JSchException e) {
            log.error("JSch error-->" + e.getMessage());
            return null;
        }
    }


    /**
     * ftp delete remote file
     *
     * @param session   session
     * @param directory directory
     * @param fileName  filename
     * @return is Success
     */
    public static boolean deleteFile(Session session, String directory, String fileName) {
        log.info(">>>>>>>>deleteFile--ftp delete file end>>>>>>>>>>>>>");
        ChannelSftp channel = null;
        try {
            channel = openSftpChannel(session);
            channel.connect(CONNECT_TIMEOUT);
            channel.rm(directory + "/" + fileName);

            log.info(">>>>>>>>deleteFile--deletefile end>>>>>>>>>>>>>");
            log.info(">>>>>>>>ftp delete file directory：{}，filename：{}>>>>>>>>>>>>>", directory, fileName);
        } catch (SftpException e) {
            log.error("ftp create directory fail" + directory);
            return false;
        } catch (JSchException e) {
            log.error("JSch error-->" + e.getMessage());
            return false;
        } finally {
            disconnect(channel);
        }

        return true;
    }

    public static Channel openChannel(Session session, String type) throws JSchException {
        if (!session.isConnected()) {
            session.connect(SESSION_TIMEOUT);
        }
        return session.openChannel(type);
    }

    public static ChannelSftp openSftpChannel(Session session) throws JSchException {
        return (ChannelSftp) openChannel(session, "sftp");
    }

    public static ChannelExec openExecChannel(Session session) throws JSchException {
        return (ChannelExec) openChannel(session, "exec");
    }

    /**
     * disconnect
     *
     * @param session
     */
    public static void disconnect(Session session) {
        if (session != null) {
            if (session.isConnected()) {
                try {
                    session.disconnect();
                    log.info("session disconnect successfully");
                } catch (Exception e) {
                    log.error("JSch session disconnect error:", e);
                }
            }
        }
    }

    /**
     * close connection
     *
     * @param channel channel connection
     */
    public static void disconnect(Channel channel) {
        if (channel != null) {
            if (channel.isConnected()) {
                try {
                    channel.disconnect();
                    log.info("channel is closed already");
                } catch (Exception e) {
                    log.error("JSch channel disconnect error:", e);
                }
            }
        }
    }

    public static int checkAck(InputStream in) throws IOException {
        int b = in.read();
        // b may be 0 for success,
        //          1 for error,
        //          2 for fatal error,
        //          -1
        if (b == 0) {
            return b;
        }
        if (b == -1) {
            return b;
        }
        if (b == 1 || b == 2) {
            StringBuilder sb = new StringBuilder();
            int c;
            do {
                c = in.read();
                sb.append((char) c);
            }
            while (c != '\n');
            if (b == 1) { // error
                log.debug(sb.toString());
            }
            if (b == 2) { // fatal error
                log.debug(sb.toString());
            }
        }
        return b;
    }

    public static void closeInputStream(InputStream in) {
        if (in != null) {
            try {
                in.close();
            } catch (IOException e) {
                log.error("Close input stream error." + e.getMessage());
            }
        }
    }

    public static void closeOutputStream(OutputStream out) {
        if (out != null) {
            try {
                out.close();
            } catch (IOException e) {
                log.error("Close output stream error." + e.getMessage());
            }
        }
    }

}

启动类Application

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

测试

package org.example;

import com.alibaba.fastjson.JSONObject;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import org.junit.After;
import org.junit.Before;
import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.List;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = DemoApplication.class)
public class AppTest {
    private Logger log = LoggerFactory.getLogger(getClass());

    Session session;
    @Before
    public void before() throws JSchException {
        Remote remote= new Remote();
        remote.setHost("xxxx");
        remote.setUser("xxxx");
        remote.setPassword("xxxx");
        session= JschUtils.getSession(remote);
    }
    @After
    public void after(){
        JschUtils.disconnect(session);
    }
    @Test
    public void remoteExecute() throws JSchException {
        List<String> list= JschUtils.remoteExecute(session,"ls");
        System.out.println(JSONObject.toJSON(list));
    }
    @Test
    public void uploadFile() throws JSchException, FileNotFoundException {
        String filestr ="D:\\tmp\\test\\file_utils\\file1.txt";
        File file = new File(filestr);
        InputStream in = new FileInputStream(file);
        String directory="/root/test";
        String fileName="test.txt";
        boolean flag= JschUtils.uploadFile(session,in,directory,fileName);
        System.out.println(flag);
    }
    @Test
    public void deleteFile() throws JSchException, FileNotFoundException {
        String directory="/root/test";
        String fileName="test.txt";
        boolean flag= JschUtils.deleteFile(session,directory,fileName);
        System.out.println(flag);
    }
    @Test
    public void scpFrom() throws JSchException, FileNotFoundException {
        String source="/root/test/file1.txt";
        String destination ="D:\\tmp\\scfFrom.txt";
        long  filesize= JschUtils.scpFrom(session,source,destination);
        System.out.println(filesize);
    }
    @Test
    public void scpTo() throws JSchException, FileNotFoundException {

        String filestr ="D:\\tmp\\test\\file_utils\\file1.txt";
        String destination="/root/test/file1.txt";
        long  filesize= JschUtils.scpTo(session,filestr,destination);
        System.out.println(filesize);
    }
}

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