[英]How to get jsch shell command output in String
我正在使用JSCH -SSH库在“ shell”通道中执行命令,但找不到找到两种方法的方法:
1)如何查找命令是否在远程unix box上完全执行?
2)如何在String中捕获命令输出,而不是在System.out控制台上打印它?
以下是我的代码段,可以在system.out上显示shell命令输出正常工作
注意:我不想使用“ exec”通道,因为它为每个命令启动一个新进程,并且不记得已导出的“ session”变量。 我必须使用“ shell”频道。
以下是我的代码段。 感谢您的帮助。感谢您的宝贵时间。
try{
String commandToRun = "ls /tmp/*.log \n";
if(channel.isClosed())
channel=session.openChannel("shell");
byte[] bytes = commandToRun.getBytes();
ByteArrayInputStream bais=new ByteArrayInputStream(bytes);
channel.setInputStream(bais);
InputStream ins=channel.getInputStream();
channel.connect();
channel.setOutputStream(System.out);//This prints on console. Need 2 capture in String somehow?
//in-efficient way to allow command to execute completely on remote Unix machine
//DO NOT know a better way, to know when command is executed completely
Thread.sleep(5000L);
}
catch(Exception e){
System.out.println("Exception in executeCommand() --->"+ e.getMessage());
e.printStackTrace();
}
OP可能不再需要我的解决方案,但是正在寻找可以同时满足这两个条件的解决方案的其他任何人:1)等待命令在远程计算机上完成; 2)将输出捕获为字符串; 您可以尝试以下方法:
public class SshConnectionManager {
private static Session session;
private static ChannelShell channel;
private static String username = "";
private static String password = "";
private static String hostname = "";
private static Session getSession(){
if(session == null || !session.isConnected()){
session = connect(hostname,username,password);
}
return session;
}
private static Channel getChannel(){
if(channel == null || !channel.isConnected()){
try{
channel = (ChannelShell)getSession().openChannel("shell");
channel.connect();
}catch(Exception e){
System.out.println("Error while opening channel: "+ e);
}
}
return channel;
}
private static Session connect(String hostname, String username, String password){
JSch jSch = new JSch();
try {
session = jSch.getSession(username, hostname, 22);
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.setPassword(password);
System.out.println("Connecting SSH to " + hostname + " - Please wait for few seconds... ");
session.connect();
System.out.println("Connected!");
}catch(Exception e){
System.out.println("An error occurred while connecting to "+hostname+": "+e);
}
return session;
}
private static void executeCommands(List<String> commands){
try{
Channel channel=getChannel();
System.out.println("Sending commands...");
sendCommands(channel, commands);
readChannelOutput(channel);
System.out.println("Finished sending commands!");
}catch(Exception e){
System.out.println("An error ocurred during executeCommands: "+e);
}
}
private static void sendCommands(Channel channel, List<String> commands){
try{
PrintStream out = new PrintStream(channel.getOutputStream());
out.println("#!/bin/bash");
for(String command : commands){
out.println(command);
}
out.println("exit");
out.flush();
}catch(Exception e){
System.out.println("Error while sending commands: "+ e);
}
}
private static void readChannelOutput(Channel channel){
byte[] buffer = new byte[1024];
try{
InputStream in = channel.getInputStream();
String line = "";
while (true){
while (in.available() > 0) {
int i = in.read(buffer, 0, 1024);
if (i < 0) {
break;
}
line = new String(buffer, 0, i);
System.out.println(line);
}
if(line.contains("logout")){
break;
}
if (channel.isClosed()){
break;
}
try {
Thread.sleep(1000);
} catch (Exception ee){}
}
}catch(Exception e){
System.out.println("Error while reading channel output: "+ e);
}
}
public static void close(){
channel.disconnect();
session.disconnect();
System.out.println("Disconnected channel and session");
}
public static void main(String[] args){
List<String> commands = new ArrayList<String>();
commands.add("ls -l");
executeCommands(commands);
close();
}
}
如果您需要一次发送多个命令并保持通道打开以供以后使用,则此解决方案也很有用。
对于2)你可以使用ByteArrayOutputStream
final ByteArrayOutputStream baos = new ByteArrayOutputStream();
channel.setOutputStream(baos);
然后new String(baos.toByteArray())
创建新的字符串
对于1,您是否尝试在命令末尾使用2>&1?
String commandToRun = "ls /tmp/*.log 2>&1 \n";
以Mihail提供的示例,互联网上的其他信息以及Martin的反馈为例,这是使用exec
进行的重新设计的解决方案。 请注意,打开一个会话允许发送多个命令,每个命令都打开其自己的输入/输出通道。
Rant :我真的很讨厌必须获取要写入的进程的OUTPUT流。 多么烦人的范例(至少对我而言)。 我想要的是将输入内容写入其中的流程输入流,并且很难解决它的反转问题。 是我还是下面的(伪代码)没有意义?
channel.getInputStream().write("here's some text to write into my channel.");
String ret = channel.getOutputStream().getOutput();
无论如何,感谢Mihail和Martin的评论/意见。
public class SSHConnectionManager {
private Session session;
private String username = "user";
private String password = "password";
private String hostname = "myhost";
public SSHConnectionManager() { }
public SSHConnectionManager(String hostname, String username, String password) {
this.hostname = hostname;
this.username = username;
this.password = password;
}
public void open() throws JSchException {
open(this.hostname, this.username, this.password);
}
public void open(String hostname, String username, String password) throws JSchException{
JSch jSch = new JSch();
session = jSch.getSession(username, hostname, 22);
Properties config = new Properties();
config.put("StrictHostKeyChecking", "no"); // not recommended
session.setConfig(config);
session.setPassword(password);
System.out.println("Connecting SSH to " + hostname + " - Please wait for few seconds... ");
session.connect();
System.out.println("Connected!");
}
public String runCommand(String command) throws JSchException, IOException {
String ret = "";
if (!session.isConnected())
throw new RuntimeException("Not connected to an open session. Call open() first!");
ChannelExec channel = null;
channel = (ChannelExec) session.openChannel("exec");
channel.setCommand(command);
channel.setInputStream(null);
PrintStream out = new PrintStream(channel.getOutputStream());
InputStream in = channel.getInputStream(); // channel.getInputStream();
channel.connect();
// you can also send input to your running process like so:
// String someInputToProcess = "something";
// out.println(someInputToProcess);
// out.flush();
ret = getChannelOutput(channel, in);
channel.disconnect();
System.out.println("Finished sending commands!");
return ret;
}
private String getChannelOutput(Channel channel, InputStream in) throws IOException{
byte[] buffer = new byte[1024];
StringBuilder strBuilder = new StringBuilder();
String line = "";
while (true){
while (in.available() > 0) {
int i = in.read(buffer, 0, 1024);
if (i < 0) {
break;
}
strBuilder.append(new String(buffer, 0, i));
System.out.println(line);
}
if(line.contains("logout")){
break;
}
if (channel.isClosed()){
break;
}
try {
Thread.sleep(1000);
} catch (Exception ee){}
}
return strBuilder.toString();
}
public void close(){
session.disconnect();
System.out.println("Disconnected channel and session");
}
public static void main(String[] args){
SSHConnectionManager ssh = new SSHConnectionManager();
try {
ssh.open();
String ret = ssh.runCommand("ls -l");
System.out.println(ret);
ssh.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
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