JSch基本使用

JSch 是SSH2的一個純Java實現。它允許你連接到一個sshd 服務器，使用端口轉發，X11轉發，文件傳輸等等。你可以將它的功能集成到你自己的 程序中。同時該項目也提供一個J2ME版本用來在手機上直連SSHD服務器。

官網:http://www.jcraft.com/jsch/中有很多例子http://www.jcraft.com/jsch/examples/，這裏先採用（已做修改）其中2個來進行簡單論述，希望對大家有所幫助。
本文采用的jsch版本是0.1.51. 下載地址：http://sourceforge.net/projects/jsch/files/jsch/0.1.54/jsch-0.1.54.zip/download。
本文采用的Linux操作系統是CentOS6.5.

TIPS: 查看Linux操作系統（內核）版本可以使用：uname -a; uname -r; cat /etc/issue; cat /etc/redhat-release等命令。

第一個例子：採用Java模擬shell操作。
這裏涉及到幾個參數，會在下面的代碼中有所體現：

• USER：所連接的Linux主機登錄時的用戶名
• PASSWORD：登錄密碼
• HOST：主機地址
• DEFAULT_SSH_PROT=端口號，默認爲22

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package com.test.jsch;   /**  * This program enables you to connect to sshd server and get the shell prompt.  * You will be asked username, hostname and passwd.  * If everything works fine, you will get the shell prompt. Output may  * be ugly because of lacks of terminal-emulation, but you can issue commands.  */   import com.jcraft.jsch.JSch; import com.jcraft.jsch.Session; import com.jcraft.jsch.UserInfo; import com.jcraft.jsch.Channel;   public class Shell{     private static final String USER="root";     private static final String PASSWORD="********";     private static final String HOST="localhost";     private static final int DEFAULT_SSH_PORT=22;       public static void main(String[] arg){           try{             JSch jsch=new JSch();             Session session = jsch.getSession(USER,HOST,DEFAULT_SSH_PORT);             session.setPassword(PASSWORD);               UserInfo userInfo = new UserInfo() {                 @Override                 public String getPassphrase() {                     System.out.println("getPassphrase");                     return null;                 }                 @Override                 public String getPassword() {                     System.out.println("getPassword");                     return null;                 }                 @Override                 public boolean promptPassword(String s) {                     System.out.println("promptPassword:"+s);                     return false;                 }                 @Override                 public boolean promptPassphrase(String s) {                     System.out.println("promptPassphrase:"+s);                     return false;                 }                 @Override                 public boolean promptYesNo(String s) {                     System.out.println("promptYesNo:"+s);                     return true;//notice here!                 }                 @Override                 public void showMessage(String s) {                     System.out.println("showMessage:"+s);                 }             };               session.setUserInfo(userInfo);               // It must not be recommended, but if you want to skip host-key check,             // invoke following,             // session.setConfig("StrictHostKeyChecking", "no");               //session.connect();             session.connect(30000);   // making a connection with timeout.               Channel channel=session.openChannel("shell");               // Enable agent-forwarding.             //((ChannelShell)channel).setAgentForwarding(true);               channel.setInputStream(System.in);       /*       // a hack for MS-DOS prompt on Windows.       channel.setInputStream(new FilterInputStream(System.in){           public int read(byte[] b, int off, int len)throws IOException{             return in.read(b, off, (len>1024?1024:len));           }         });        */               channel.setOutputStream(System.out);         /*       // Choose the pty-type "vt102".       ((ChannelShell)channel).setPtyType("vt102");       */         /*       // Set environment variable "LANG" as "ja_JP.eucJP".       ((ChannelShell)channel).setEnv("LANG", "ja_JP.eucJP");       */               //channel.connect();             channel.connect(3*1000);         }         catch(Exception e){             System.out.println(e);         }     } }

運行結果：

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promptYesNo: The authenticity of host '10.101.139.5' can't be established. RSA key fingerprint is 59:0f:32:fc:7b:54:3d:90:c0:ef:5a:6b:fb:11:55:e1. Are you sure you want to continue connecting? trueLast login: Thu Sep 29 18:40:56 2016 from 10.101.48.240 [root@hidden ~]#

輸入ls查看：

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(省略一些....) [root@hidden ~]# ls ls 1.txt            install.log.syslog  vmware-tools-distrib  模板  文檔  桌面 anaconda-ks.cfg  logs                workspace             視頻  下載 install.log      util                公共的                圖片  音樂 [root@hidden ~]#

這樣就和在原linux系統中一樣使用shell功能了。

如果需要跳過如下的檢測：

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The authenticity of host '10.101.139.5' can't be established. RSA key fingerprint is 59:0f:32:fc:7b:54:3d:90:c0:ef:5a:6b:fb:11:55:e1. Are you sure you want to continue connecting?

只需要在程序中加入相應的代碼：

1	session.setConfig("StrictHostKeyChecking", "no");

運行結果：

1 2	Last login: Thu Sep 29 18:39:18 2016 from 10.101.48.240 [root@hidden ~]#

第二個例子：運行一條shell指令，這裏就那“ls”做例子好了。

No more talk, show you the code:

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package com.test.jsch;   import com.jcraft.jsch.*; import java.io.*;   public class Exec{     private static final String USER="root";     private static final String PASSWORD="********";     private static final String HOST="localhost";     private static final int DEFAULT_SSH_PORT=22;       public static void main(String[] arg){         try{             JSch jsch=new JSch();               Session session = jsch.getSession(USER,HOST,DEFAULT_SSH_PORT);             session.setPassword(PASSWORD);               // username and password will be given via UserInfo interface.             session.setUserInfo(new MyUserInfo());             session.connect();               String command="ls";               Channel channel=session.openChannel("exec");             ((ChannelExec)channel).setCommand(command);               // X Forwarding             // channel.setXForwarding(true);               //channel.setInputStream(System.in);             channel.setInputStream(null);               //channel.setOutputStream(System.out);               //FileOutputStream fos=new FileOutputStream("/tmp/stderr");             //((ChannelExec)channel).setErrStream(fos);             ((ChannelExec)channel).setErrStream(System.err);               InputStream in=channel.getInputStream();               channel.connect();               byte[] tmp=new byte[1024];             while(true){                 while(in.available()>0){                     int i=in.read(tmp, 0, 1024);                     if(i<0)break;                     System.out.print(new String(tmp, 0, i));                 }                 if(channel.isClosed()){                     if(in.available()>0) continue;                     System.out.println("exit-status: "+channel.getExitStatus());                     break;                 }                 try{Thread.sleep(1000);}catch(Exception ee){}             }             channel.disconnect();             session.disconnect();         }         catch(Exception e){             System.out.println(e);         }     }       private static class MyUserInfo implements UserInfo{         @Override         public String getPassphrase() {             System.out.println("getPassphrase");             return null;         }         @Override         public String getPassword() {             System.out.println("getPassword");             return null;         }         @Override         public boolean promptPassword(String s) {             System.out.println("promptPassword:"+s);             return false;         }         @Override         public boolean promptPassphrase(String s) {             System.out.println("promptPassphrase:"+s);             return false;         }         @Override         public boolean promptYesNo(String s) {             System.out.println("promptYesNo:"+s);             return true;//notice here!         }         @Override         public void showMessage(String s) {             System.out.println("showMessage:"+s);         }     } }

運行結果：

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promptYesNo:The authenticity of host '10.101.139.5' can't be established. RSA key fingerprint is 59:0f:32:fc:7b:54:3d:90:c0:ef:5a:6b:fb:11:55:e1. Are you sure you want to continue connecting? 1.txt anaconda-ks.cfg install.log install.log.syslog logs util vmware-tools-distrib workspace 公共的 模板 視頻 圖片 文檔 下載 音樂 桌面 exit-status: 0

第二個例子相比於第一個例子來說將UserInfo採用static class的方式提取出來，這樣更直觀一點。

JSch是以多線程方式一下，所以代碼在connect後如果不disconnect channel和session,以及相關stream, 程序會一直等待，直到關閉。

需要注意的一個問題，相關的Stream和Channel是一定要關閉的，那麼應該在什麼時候來關？執行connect後，JSch接受客戶端結果需要一定的時間（以秒計），如果馬上關閉session就會發現什麼都沒接受到或內容不全。

還有一點注意，使用shell時，看到執行後沒有結果，解決辦法是在命令行後加上”\n”字符，server端就認爲是一條完整的命令了。

最後將第一個和第二個例子合併，並提取一些公用模塊，以便更好的理解和使用：

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package com.test.jsch;   import com.jcraft.jsch.*;   import java.io.*; import java.util.concurrent.TimeUnit;   import static java.lang.String.format;   /**  * Created by hidden on 2016/9/29.  */ public class SSHExecutor {     private static long INTERVAL = 100L;     private static int SESSION_TIMEOUT = 30000;     private static int CHANNEL_TIMEOUT = 3000;     private JSch jsch = null;     private Session session = null;       private SSHExecutor(SSHInfo sshInfo) throws JSchException {         jsch =new JSch();         session = jsch.getSession(sshInfo.getUser(),sshInfo.getHost(),sshInfo.getPort());         session.setPassword(sshInfo.getPassword());         session.setUserInfo(new MyUserInfo());         session.connect(SESSION_TIMEOUT);     }       /*     * 在這裏修改訪問入口,當然可以把這個方法弄到SSHExecutor外面，這裏是方便操作才這麼做的     * */     public static SSHExecutor newInstance() throws JSchException {         SSHInfo sshInfo = new SSHInfo("root","******","locahost",22);         return new SSHExecutor(sshInfo);     }       /*     * 注意編碼轉換     * */     public long shell(String cmd, String outputFileName) throws JSchException, IOException, InterruptedException {         long start = System.currentTimeMillis();         Channel channel = session.openChannel("shell");         PipedInputStream pipeIn = new PipedInputStream();         PipedOutputStream pipeOut = new PipedOutputStream( pipeIn );         FileOutputStream fileOut = new FileOutputStream( outputFileName, true);         channel.setInputStream(pipeIn);         channel.setOutputStream(fileOut);         channel.connect(CHANNEL_TIMEOUT);           pipeOut.write(cmd.getBytes());         Thread.sleep( INTERVAL );         pipeOut.close();         pipeIn.close();         fileOut.close();         channel.disconnect();         return System.currentTimeMillis() - start;     }       public int exec(String cmd) throws IOException, JSchException, InterruptedException {         ChannelExec channelExec = (ChannelExec)session.openChannel( "exec" );         channelExec.setCommand( cmd );         channelExec.setInputStream( null );         channelExec.setErrStream( System.err );         InputStream in = channelExec.getInputStream();         channelExec.connect();           int res = -1;         StringBuffer buf = new StringBuffer( 1024 );         byte[] tmp = new byte[ 1024 ];         while ( true ) {             while ( in.available() > 0 ) {                 int i = in.read( tmp, 0, 1024 );                 if ( i < 0 ) break;                 buf.append( new String( tmp, 0, i ) );             }             if ( channelExec.isClosed() ) {                 res = channelExec.getExitStatus();                 System.out.println( format( "Exit-status: %d", res ) );                 break;             }             TimeUnit.MILLISECONDS.sleep(100);         }         System.out.println( buf.toString() );         channelExec.disconnect();         return res;     }       public Session getSession(){         return session;     }       public void close(){         getSession().disconnect();     }       /*     * SSH連接信息     * */     public static class SSHInfo{         private String user;         private String password;         private String host;         private int port;           public SSHInfo(String user, String password, String host, int port) {             this.user = user;             this.password = password;             this.host = host;             this.port = port;         }           public String getUser() {             return user;         }           public String getPassword() {             return password;         }           public String getHost() {             return host;         }           public int getPort() {             return port;         }     }       /*     * 自定義UserInfo     * */     private static class MyUserInfo implements UserInfo{           @Override public String getPassphrase() { return null; }           @Override public String getPassword() { return null; }           @Override public boolean promptPassword(String s) { return false; }           @Override public boolean promptPassphrase(String s) { return false; }           @Override         public boolean promptYesNo(String s) {             System.out.println(s);             System.out.println("true");             return true;         }           @Override public void showMessage(String s) { }     } }

測試代碼：

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SSHExecutor ssh =  SSHExecutor.newInstance(); System.out.println("================"); long shell1 = ssh.shell("ls\n","C:\\Users\\hidden\\Desktop\\shell.txt"); long shell2 = ssh.shell("pwd\n","C:\\Users\\hidden\\Desktop\\shell.txt"); System.out.println("shell 1 執行了"+shell1+"ms"); System.out.println("shell 2 執行了"+shell2+"ms"); System.out.println("================"); int cmd1 = ssh.exec("ls\n"); ssh.close();

測試結果：

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The authenticity of host '10.101.139.5' can't be established. RSA key fingerprint is 59:0f:32:fc:7b:54:3d:90:c0:ef:5a:6b:fb:11:55:e1. Are you sure you want to continue connecting? true ================ shell 1 執行了142ms shell 2 執行了132ms ================ Exit-status: 0 1.txt anaconda-ks.cfg install.log install.log.syslog logs util vmware-tools-distrib workspace 公共的 模板 視頻 圖片 文檔 下載 音樂 桌面

還有解釋查看一下左邊是否有個shell.txt以及shell.txt是否有相應的內容。