我们经常使用一些ssh的终端工具如xshell,iterm,securecrt与远程服务器进行交互,那么有没有直接通过Java程序与远端服务器交互方式呢？此系列文章将带你走进Java SSH的世界。
Ganymed SSH2是一个纯Java实现SSH2协议的库，我们可以通过它使我们的Java程序直接连接ssh servers, 并且支持会话保持。
废话不多说，直接来实践吧。
你可以通过Maven引入或者导入源码或者导入jar包。
maven
<!-- https://mvnrepository.com/artifact/ch.ethz.ganymed/ganymed-ssh2 -->
<dependency>
<groupId>ch.ethz.ganymed</groupId>
<artifactId>ganymed-ssh2</artifactId>
<version>262</version>
</dependency>
源码
https://github.com/hudson/ganymed-ssh-2
为了让大家对它有个直观的认识，我们先从一个最简单的示例入手。
下面的例子实现连接我的Mac机器，执行一条命令，然后获取命令的输出。
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import ch.ethz.ssh2.Connection;
import ch.ethz.ssh2.Session;
import ch.ethz.ssh2.StreamGobbler;
public class Basic {
public static void main(String[] args) {
String hostname = "192.168.0.103";
String username = "chinaxiang";
String password = "asdf";
try {
Connection conn = new Connection(hostname);
conn.connect();
boolean isAuthenticated = conn.authenticateWithPassword(username, password);
if (isAuthenticated == false)
throw new IOException("Authentication failed.");
Session sess = conn.openSession();
sess.execCommand("uname -a && date && uptime && who");
System.out.println("Here is some information about the remote host:");
InputStream stdout = new StreamGobbler(sess.getStdout());
BufferedReader br = new BufferedReader(new InputStreamReader(stdout));
while (true) {
String line = br.readLine();
if (line == null)
break;
System.out.println(line);
}
System.out.println("ExitCode: " + sess.getExitStatus());
br.close();
sess.close();
conn.close();
} catch (IOException e) {
e.printStackTrace(System.err);
System.exit(2);
}
}
}
执行，输出如下：
Here is some information about the remote host:
Darwin bogon 16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 x86_64
Sun Jan 21 22:37:48 CST 2018
22:37 up 73 days, 3:22, 3 users, load averages: 1.34 1.52 1.52
chinaxiang console Nov 9 19:17
chinaxiang ttys001 Jan 8 09:34
chinaxiang ttys002 Jan 20 21:49
ExitCode: null
为了避免不暴露密码，我们可以配置ssh免密码认证。
ssh-keygen -t rsa -P ''
ssh-copy-id user@ip
下面的示例是使用密钥免密码登录我的Mac机器。
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import ch.ethz.ssh2.Connection;
import ch.ethz.ssh2.Session;
import ch.ethz.ssh2.StreamGobbler;
public class PublicKeyAuthentication {
public static void main(String[] args) {
String hostname = "192.168.0.103";
String username = "chinaxiang";
File keyfile = new File("/Users/chinaxiang/.ssh/id_rsa"); // 密钥
String keyfilePass = ""; // will be ignored if not needed
try {
Connection conn = new Connection(hostname);
conn.connect();
boolean isAuthenticated = conn.authenticateWithPublicKey(username, keyfile, keyfilePass);
if (isAuthenticated == false)
throw new IOException("Authentication failed.");
Session sess = conn.openSession();
sess.execCommand("uname -a && date && uptime && who");
InputStream stdout = new StreamGobbler(sess.getStdout());
BufferedReader br = new BufferedReader(new InputStreamReader(stdout));
System.out.println("Here is some information about the remote host:");
while (true) {
String line = br.readLine();
if (line == null)
break;
System.out.println(line);
}
br.close();
sess.close();
conn.close();
} catch (IOException e) {
e.printStackTrace(System.err);
System.exit(2);
}
}
}
输出内容如下：
Here is some information about the remote host:
Darwin bogon 16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 x86_64
Sun Jan 21 22:59:57 CST 2018
22:59 up 73 days, 3:44, 3 users, load averages: 1.45 1.56 1.56
chinaxiang console Nov 9 19:17
chinaxiang ttys001 Jan 8 09:34
chinaxiang ttys002 Jan 20 21:49
上面我们只获取了标准输出，没有获取标准错误输出。
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import ch.ethz.ssh2.Connection;
import ch.ethz.ssh2.Session;
import ch.ethz.ssh2.StreamGobbler;
public class StdoutAndStderr {
public static void main(String[] args) {
String hostname = "192.168.0.103";
String username = "chinaxiang";
String password = "asdf";
try {
Connection conn = new Connection(hostname);
conn.connect();
boolean isAuthenticated = conn.authenticateWithPassword(username, password);
if (isAuthenticated == false)
throw new IOException("Authentication failed.");
Session sess = conn.openSession();
sess.execCommand("echo \"Text on STDOUT\"; echo \"Text on STDERR\" >&2");
InputStream stdout = new StreamGobbler(sess.getStdout());
InputStream stderr = new StreamGobbler(sess.getStderr());
BufferedReader stdoutReader = new BufferedReader(new InputStreamReader(stdout));
BufferedReader stderrReader = new BufferedReader(new InputStreamReader(stderr));
System.out.println("Here is the output from stdout:");
while (true) {
String line = stdoutReader.readLine();
if (line == null)
break;
System.out.println(line);
}
System.out.println("Here is the output from stderr:");
while (true) {
String line = stderrReader.readLine();
if (line == null)
break;
System.out.println(line);
}
stdoutReader.close();
stderrReader.close();
sess.close();
conn.close();
} catch (IOException e) {
e.printStackTrace(System.err);
System.exit(2);
}
}
}
执行结果：
Here is the output from stdout:
Text on STDOUT
Here is the output from stderr:
Text on STDERR