如何阅读JSch命令输出？ [英] How to read JSch command output?

问题描述

我有以下代码：

  JSch jsch = new JSch（）; 
 jsch.setKnownHosts（dotSshDir +/ known_hosts）; 
 jsch.addIdentity（dotSshDir +/ id_rsa）; 
 
会话session = jsch.getSession（userName，hostname，22）; 
 session.connect（）; 
 
 ChannelExec channel =（ChannelExec）session.openChannel（exec）; 
 channel.setCommand（command）; 
 channel.setInputStream（null）; 
 channel.setErrStream（System.err）; 
 Reader reader = new InputStreamReader（channel.getInputStream（））; 
 
 char [] buf = new char [1024]; 
 int numRead; 
 while（（numRead = reader.read（buf））！= -1）{
 String readData = String.valueOf（buf，0，numRead）; 
 result.append（readData）; 
 buf = new char [1024]; 
} 
  

它正试图从阅读器上读取。我该如何解决？我该怎么做才能找到正在发生的事情？

解决方案

悬挂实际上是由于命令中的一些不平衡报价。

对于后代，最终代码（在处理其他一些问题之后）是：

  public String call（String hostname，String [] argv）抛出SubprocessException {
 StringBuffer result = new StringBuffer（）; 
 
会话session = null; 
 ChannelExec channel = null; 
 
 try {
 // TODO：如果〜/ .ssh不存在，则发出友好错误。 
 String dotSshDir = System.getProperty（user.home）+/。shh; 
 String userName = System.getProperty（user.name）; 
 
 // TODO：如果〜/ .ssh / known_hosts不存在，则发出友好错误。 
 jSch.setKnownHosts（dotSshDir +/ known_hosts）; 
 // TODO：如果〜/ .ssh / id_rsa不存在，则发出友好错误。 
 jSch.addIdentity（dotSshDir +/ id_rsa）; 
 
 session = jSch.getSession（userName，hostname，22）; 
 session.connect（）; 
 
 channel =（ChannelExec）session.openChannel（exec）; 
 channel.setCommand（Joiner.on（）。join（argv））; 
 channel.setInputStream（null）; 
 InputStream stdout = channel.getInputStream（）; 
 InputStream stderr = channel.getErrStream（）; 
 channel.connect（）; 
 
 waitForChannelClosed（channel）; 
 
 if（channel.getExitStatus（）！= 0）{
 BufferedReader bufferedReader = new BufferedReader（new InputStreamReader（stderr））; 
 readAll（bufferedReader，result）; 
 
抛出新的异常（result.toString（））; 
} else {
 BufferedReader bufferedReader = new BufferedReader（new InputStreamReader（stdout））; 
 readAll（bufferedReader，result）; 
} 
} catch（例外e）{
抛出新的SubprocessException（e）; 
} finally {
 if（channel！= null）{
 channel.disconnect（）; 
} 
 
 if（session！= null）{
 session.disconnect（）; 
} 
} 
 
返回result.toString（）; 
} 
  

I have the following code:

JSch jsch = new JSch();
jsch.setKnownHosts(dotSshDir + "/known_hosts");
jsch.addIdentity(dotSshDir + "/id_rsa");

Session session = jsch.getSession(userName, hostname, 22);
session.connect();

ChannelExec channel = (ChannelExec) session.openChannel("exec");
channel.setCommand(command);
channel.setInputStream(null);
channel.setErrStream(System.err);
Reader reader = new InputStreamReader(channel.getInputStream());

char[] buf = new char[1024];
int numRead;
while ((numRead = reader.read(buf)) != -1) {
    String readData = String.valueOf(buf, 0, numRead);
    result.append(readData);
    buf = new char[1024];
}

It's hanging trying to read from the reader. How do I fix this? How do I go about hunting down what's happening?

解决方案

The hanging was actually due to some unbalanced quotes in the command.

For posterity, the final code (after dealing with some other issues) is:

public String call(String hostname, String[] argv) throws SubprocessException {
    StringBuffer result = new StringBuffer();

    Session session = null;
    ChannelExec channel = null;

    try {
        // TODO: Emit friendly error if ~/.ssh doesn't exist.
        String dotSshDir = System.getProperty("user.home") + "/.ssh";
        String userName = System.getProperty("user.name");

        // TODO: Emit friendly error if ~/.ssh/known_hosts doesn't exist.
        jSch.setKnownHosts(dotSshDir + "/known_hosts");
        // TODO: Emit friendly error if ~/.ssh/id_rsa doesn't exist.
        jSch.addIdentity(dotSshDir + "/id_rsa");

        session = jSch.getSession(userName, hostname, 22);
        session.connect();

        channel = (ChannelExec) session.openChannel("exec");
        channel.setCommand(Joiner.on(" ").join(argv));
        channel.setInputStream(null);
        InputStream stdout = channel.getInputStream();
        InputStream stderr = channel.getErrStream();
        channel.connect();

        waitForChannelClosed(channel);

        if (channel.getExitStatus() != 0) {
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(stderr));
            readAll(bufferedReader, result);

            throw new Exception(result.toString());
        } else {
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(stdout));
            readAll(bufferedReader, result);
        }
    } catch (Exception e) {
        throw new SubprocessException(e);
    } finally {
        if (channel != null) {
            channel.disconnect();
        }

        if (session != null) {
            session.disconnect();
        }
    }

    return result.toString();
}

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