Develop Reference

Adding double quotes symbol in ProcessBuilder

I am using ProcessBuilderto build my command. I want to build my command following this post:How do I launch a java process that has the standard bash shell environment?
Namely, my command is something like this:
/bin/bash -l -c "my program"
However, I am having difficulties to pass the double quotes into ProcessBuilder, as new ProcessBuilder(List<String> command) failed to phrase the command if I natively add double quotes to List<String> command. ProcessBuilder recognizes the double quotes as an argument.
Relevant code:
//Construct the argument
csi.add("/bin/bash");
csi.add("-l");
csi.add("-c");
csi.add("\"");
csi.add(csi_path);
csi.add(pre_hash);
csi.add(post_hash);
csi.add("\"");
String csi_output = Command.runCommand(project_directory, csi);
public static String runCommand(String directory, List<String> command) {
ProcessBuilder processBuilder = new ProcessBuilder(command).directory(new File(directory));
Process process;
String output = null;
try {
process = processBuilder.start();
//Pause the current thread until the process is done
process.waitFor();
//When the process does not exit properly
if (process.exitValue() != 0) {
//Error
System.out.println("command exited in error: " + process.exitValue());
//Handle the error
return readOutput(process);
}else {
output = readOutput(process);
System.out.println(output);
}
} catch (InterruptedException e) {
System.out.println("Something wrong with command: " +e.getMessage());
} catch (IOException e) {
System.out.println("Something wrong with command: " +e.getMessage());
}
return output;
}
Ps: I do want to use ProcessBuilder instead of Runtime.getRuntime.exec() because I need to run the command in a specific directory. I need to use ProcessBuilder.directory().
Ps: The command will exit with 2 after running. It seems that the system can recognize this command. The strange thing is that it has no output after exiting with 2.
Ps: The expected command is /bin/bash -l -c "/Users/ryouyasachi/GettyGradle/build/idea-sandbox/plugins/Getty/classes/python/csi 19f4281 a562db1". I printed the value and it was correct.

Best way to troubleshoot your problem is to construct the command first and pass it to the list. So, instead of doing all this.
csi.add("/bin/bash");
csi.add("-l");
csi.add("-c");
csi.add("\"");
csi.add(csi_path);
csi.add(pre_hash);
csi.add(post_hash);
csi.add("\"");
You should first construct the command
StringBuilder sb = new StringBuilder();
sb.append("/bin/bash -l -c");
sb.append("\""+csi_path+pre_hash+post_hash+"\"");// add whitespace between the varaible, if required.
System.outprintln(sb.toString()); //verify your command here
csi.add(sb.toString());
Also, verify all above variable values.

Thx for #Ravi 's idea!
//Construct the argument
csi.add("/bin/bash");
csi.add("-l");
csi.add("-c");
csi.add("\"" + csi_path + " " + pre_hash+ " " + post_hash + "\"");
String csi_output = Command.runCommand(project_directory, csi);
The Process has to take each argument separately in order to recognize the command. The tricky part is that, in my desired command
/bin/bash -l -c "/mypath/csi"
"/mypath/csi" needs to be viewed as one single argument by Process.

How to make Runtime.getRuntime().exec execute command one by one and get output rather than executing all commands

I am trying to run a *.bat file (which is capable of running several commands and retrieve the output one by one) from my java application. My intention is to send one command, read output use this output for second command and again retrieve the output.
To achieve this, through Runtime.getRuntime().exec I am passing more than one command as an input to PrintWriter. Issue is that after completing all the steps only I can read the output from *.bat through buffer ,but my intention is to run one command get the output and manipulate this output to send second command.
Unfortunately is not working. Any resolution for this?..
I got the idea to send more than one command to Runtime.getRuntime().exec from this link (How to execute cmd commands via Java)
The following is the same code which I got from above link
String[] command =
{
"cmd",
};
Process p = Runtime.getRuntime().exec(command);
new Thread(new SyncPipe(p.getErrorStream(), System.err)).start();
new Thread(new SyncPipe(p.getInputStream(), System.out)).start();
PrintWriter stdin = new PrintWriter(p.getOutputStream());
stdin.println("dir c:\\ /A /Q");
// write any other commands you want here
stdin.close();
int returnCode = p.waitFor();
System.out.println("Return code = " + returnCode);
class SyncPipe implements Runnable
{
public SyncPipe(InputStream istrm, OutputStream ostrm) {
istrm_ = istrm;
ostrm_ = ostrm;
}
public void run() {
try
{
final byte[] buffer = new byte[1024];
for (int length = 0; (length = istrm_.read(buffer)) != -1; )
{
ostrm_.write(buffer, 0, length);
}
}
catch (Exception e)
{
e.printStackTrace();
}
}
private final OutputStream ostrm_;
private final InputStream istrm_;
}

In your case I would not use Threads, you want a sequential execution path.

Actually, instead of trying to reinvent the wheel, I strongly suggest you to use an expect-like java library to do that kind of thing.
Just because there are several things that you'll have to deal with, such as timeout between requests, waiting for the output to return, etc.
Take a look at these libraries
http://expectj.sourceforge.net/
https://code.google.com/p/expect4j/
https://github.com/ronniedong/Expect-for-Java
http://code.google.com/p/enchanter/
In particular, I use expectj in my project and it works pretty well (although I think expect4j is more popular)
With expectj, your code will look like this (from http://expectj.sourceforge.net/)
// Create a new ExpectJ object with a timeout of 5s
ExpectJ expectinator = new ExpectJ(5);
// Fork the process
Spawn shell = expectinator.spawn("/bin/sh");
// Talk to it
shell.send("echo Chunder\n");
shell.expect("Chunder");
shell.send("exit\n");
shell.expectClose();

You can do the redirection of output of one command to other in the bat file itself using pipe.
I am sorry, i hadn't noticed that you want to manipulate the output first.
So instead of using bat file, you can run the commands that are in bat file from java using exec , get the out put, and use the out put to execute the next command.

Runtime.exec().waitFor() not actually waiting for

I've got some code that uses Runtime.exec() to run an external .jar (built as an IzPack installer).
If I run this external.jar from the command line like so:
java -jar external.jar
Then the command prompt does not return control until the application is finished. However, if I run external.jar from within some java class, using:
Process p = Runtime.getRuntime().exec("java -jar external.jar");
int exitCode = p.waitFor();
System.out.println("Process p returned: " + exitCode);
Then p returns almost instantly with a success code of 0, despite external.jar having not yet completed execution (i've also tried this via the ProcessBuilder route of external file execution).
Why does it wait to return from the command line, but not when executed from within another java program?
I've also set up 3 jars, A, B and C where A calls B which calls C (using Runtime.exec()), where C Thread.sleeps for 10 seconds, as a simple test, and as expected, A doesn't return until 10 seconds after it runs.
I figure this is probably some kind of a threading issue with external.jar where execution is being handed over from one thing to another, but given that it works directly from the command line i kind of expected to see the same behaviour (perhaps naively) when called from within another java program.
I've tested this on Windows and Ubuntu with Java 6.
Thanks!

another possible way to achieve this might be to capture the output of the process and wait for it to finish.
For example:
Process tr = Runtime.getRuntime().exec( new String[]{"wkhtmltopdf",mainPage,mainPagePDF});
BufferedReader stdOut=new BufferedReader(new InputStreamReader(tr.getInputStream()));
String s;
while((s=stdOut.readLine())!=null){
//nothing or print
}
Normally the output stream is tr.getInputStream() but depending on the program you are executing the process output stream migh be:
tr.getInputStream()
tr.getErrorStream()
tr.getOutputStream()
By doing this while loop you force your program to wait the process to finish.

You can use Process Builder....
ProcessBuilder pb = new ProcessBuilder("java", "-jar", "/fielname.jar");
Process p = pb.start();
p.waitFor();

Are you spawning a new thread to handle the spawning of the process? If so the origional program will continue to operate independently of the spawned process and therefore waitFor() will only work on the new process and not the parent.

Process.waitFor() is useless for some native system command.
You need to get the process's output to determine if it is returned.
I wrote a sample code for you
/**
*
* #param cmdarray command and parameter of System call
* #param dir the directory execute system call
* #param returnImmediately true indicate return after system call immediately;
* false otherwise.
* if set true, the returned call result does not have reference value
* #return the return code of system call , default is -1
*/
public static int systemCall(String[] cmdarray,File dir,boolean returnImmediately)
{
int result = -1;
try {
Process p = Runtime.getRuntime().exec(cmdarray,null,dir);
if(!returnImmediately)
{
java.io.InputStream stdin = p.getInputStream();
java.io.InputStreamReader isr = new java.io.InputStreamReader(stdin);
java.io.BufferedReader br = new java.io.BufferedReader(isr);
String line = null;
while ( (line = br.readLine()) != null)
System.out.println(line);
}
try{result = p.exitValue();}
catch(Exception ie){;}
} catch (IOException e) {
e.printStackTrace();}
return result;
}
public static void main(String[] argc){
String[] cmdarray = {"jar","cvf","s2.jar","*"};
File dir = new File("D:\\src\\struts-2.3.1");
int k = systemCall(cmdarray,dir,true);
System.out.println("k="+k);
}

I had the same problem using processs to execute some software using the console, and i just solved it using process.waitFor()
For me it worked perfectly.
try{
Process tr = Runtime.getRuntime().exec( new String[]{ "wkhtmltopdf",frontPage,frontPagePDF});
tr.waitFor();
} catch (Exception ex) {
EverLogger.logEntry("Error al pasar a PDF la portada", "error", "activity");
return;
}
some more code here.

How to execute a interactive shell script using java Runtime?

I am wondering is there any way to execute following shell script, which waits for user input using java's Runtime class?
#!/bin/bash
echo "Please enter your name:"
read name
echo "Welcome $name"
I am using following java code to do this task but it just shows blank console.
public class TestShellScript {
public static void main(String[] args) {
File wd = new File("/mnt/client/");
System.out.println("Working Directory: " +wd);
Process proc = null;
try {
proc = Runtime.getRuntime().exec("sudo ./test.sh", null, wd);
} catch (Exception e) {
e.printStackTrace();
}
}
}
Thing is when I execute above program, I believed it will execute a shell script and that shell script will wait for user input, but it just prints current directory and then exits. Is there any way to do this or it is not possible at all in java?
Thanks in advance

The reason it prints the current dir and exits is because your java app exits. You need to add a (threaded) listener to the input and error streams of your created process, and you'll probably want to add a printStream to the process's output stream
example:
proc = Runtime.getRuntime().exec(cmds);
PrintStream pw = new PrintStream(proc.getOutputStream());
FetcherListener fl = new FetcherListener() {
#Override
public void fetchedMore(byte[] buf, int start, int end) {
textOut.println(new String(buf, start, end - start));
}
#Override
public void fetchedAll(byte[] buf) {
}
};
IOUtils.loadDataASync(proc.getInputStream(), fl);
IOUtils.loadDataASync(proc.getErrorStream(), fl);
String home = System.getProperty("user.home");
//System.out.println("home: " + home);
String profile = IOUtils.loadTextFile(new File(home + "/.profile"));
pw.println(profile);
pw.flush();
To run this, you will need to download my sourceforge project: http://tus.sourceforge.net/ but hopefully the code snippet is instructive enough that you can just adapt to J2SE and whatever else you are using.

If you use a Java ProcessBuilder you should be able to get the Input, Error and Output streams of the Process you create.
These streams can be used to get information coming out of the process (like prompts for input) but they can also be written to to put information into the process directly too. For instance:
InputStream stdout = process.getInputStream ();
BufferedReader reader = new BufferedReader (new InputStreamReader(stdout));
String line;
while(true){
line = reader.readLine();
//...
That'll get you the output from the process directly. I've not done it myself, but I'm pretty sure that process.getOutputStream() gives you something that can be written to directly to send input to the process.

The problem with running interactive programs, such as sudo, from Runtime.exec is that it attaches their stdin and stdout to pipes rather than the console device they need. You can make it work by redirecting the input and output to /dev/tty.
You can achieve the same behaviour using the new ProcessBuilder class, setting up the redirection using ProcessBuilder.Redirect.INHERIT.

Note sure at all you can send input to your script from Java. However I very strongly recommend to have a look at Commons Exec if you are to execute external scripts from Java:
Commons Exec homepage
Commons Exec API

Reading InputStream from a batch file's process skips to next line

I am trying to run a batch file with Runtime.exec() and then output its InputStream into a JTextArea. What I have works, but only partially. What happens is the batch file runs, but if it executes a command other than something like "echo" that command immediately terminates and the next line executes. For example, let's say I try to run a simple batch file like this:
#echo off
echo hello. waiting 5 seconds.
timeout /t 5 /nobreak > NUL
echo finished. goodbye.
The batch file executes, and the JTextArea says
hello. waiting 5 seconds.
finished. goodbye.
but it doesn't wait for 5 seconds in the middle.
I can't figure out why it's doing this. Here's what I use to run the batch file and read its InputStream.
private class ScriptRunner implements Runnable {
private final GUI.InfoGUI gui; // the name of my GUI class
private final String script;
public ScriptRunner(final GUI.InfoGUI gui, final File script) {
this.gui = gui;
this.script = script.getAbsolutePath();
}
#Override
public void run() {
try {
final Process p = Runtime.getRuntime().exec(script);
StreamReader output = new StreamReader(p.getInputStream(), gui);
Thread t = new Thread(output);
t.start();
int exit = p.waitFor();
output.setComplete(true);
while (t.isAlive()) {
sleep(500);
}
System.out.println("Processed finished with exit code " + exit);
} catch (final Exception e) {
e.printStackTrace();
}
}
}
private class StreamReader implements Runnable {
private final InputStream is;
private final GUI.InfoGUI gui;
private boolean complete = false;
public StreamReader(InputStream is, GUI.InfoGUI gui) {
this.is = is;
this.gui = gui;
}
#Override
public void run() {
BufferedReader in = new BufferedReader(new InputStreamReader(is));
try {
while (!complete || in.ready()) {
while (in.ready()) {
gui.setTextAreaText(in.readLine() + "\n");
}
sleep(250);
}
} catch (final Exception e) {
e.printStackTrace();
} finally {
try {
in.close();
} catch (final Exception e) {
e.printStackTrace();
}
}
public void setComplete(final boolean complete) {
this.complete = complete;
}
}
public void sleep(final long ms) {
try {
Thread.sleep(ms);
} catch (final InterruptedException ie) {
}
}
I know my code is pretty messy, and I'm sure it contains grammatical errors.
Thanks for anything you can do to help!

You're creating a Process but you're not reading from its standard error stream. The process might be writing messages to its standard error to tell you that there's a problem, but if you're not reading its standard error, you won't be able to read these messages.
You have two options here:
Since you already have a class that reads from a stream (StreamReader), wire up another one of these to the process's standard error stream (p.getErrorStream()) and run it in another Thread. You'll also need to call setComplete on the error StreamReader when the call to p.waitFor() returns, and wait for the Thread running it to die.
Replace your use of Runtime.getRuntime().exec() with a ProcessBuilder. This class is new in Java 5 and provides an alternative way to run external processes. In my opinion its most significant improvement over Runtime.getRuntime().exec() is the ability to redirect the process's standard error into its standard output, so you only have one stream to read from.
I would strongly recommend going for the second option and choosing to redirect the process's standard error into its standard output.
I took your code and replaced the line
final Process p = Runtime.getRuntime().exec(script);
with
final ProcessBuilder pb = new ProcessBuilder(script);
pb.redirectErrorStream(true);
final Process p = pb.start();
Also, I don't have your GUI code to hand, so I wrote the output of the process to System.out instead.
When I ran your code, I got the following output:
hello. waiting 5 seconds.
ERROR: Input redirection is not supported, exiting the process immediately.
finished. goodbye.
Processed finished with exit code 0
Had you seen that error message, you might have twigged that something was up with the timeout command.
Incidentally, I noticed in one of your comments that none of the commands suggested by ughzan worked. I replaced the timeout line with ping -n 5 127.0.0.1 > NUL and the script ran as expected. I couldn't reproduce a problem with this.

The problem is definitely in timeout.exe. If you add echo %errorlevel% after line with timeout, you will see that it returns 1 if running from java. And 0 if running in usual way. Probably, it requires some specific console functionality (i.e. cursor positioning) that is suppressed when running from java process.
Is there anything I can do to get this to work while running from Java
If you don't need ability to run any batch file then consider to replace timeout with ping. Otherwise... I've tried to run batch file with JNA trough Kernel32.CreateProcess and timeout runs fine. But then you need to implement reading of process output trough native calls also.
I hope someone will suggest better way.

The ready method only tells if the stream can guarantee that something can be read immediately, without blocking. You can't really trust it because always returning false is a valid implementation. Streams with buffers may return true only when they have something buffered. So I suspect your problem is here:
while (!complete || in.ready()) {
while (in.ready()) {
gui.setTextAreaText(in.readLine() + "\n");
}
sleep(250);
}
It should rather read something like this:
String line;
while (!complete || (line=in.readLine()) != null) {
gui.setTextAreaText(line + "\n");
}

It's probably because your "timeout ..." command returned with an error.
Three ways to test it:
Check if the "timeout ..." command works in the Windows command prompt.
Replace "timeout ..." in the script with "ping -n 5 127.0.0.1 > NUL" (it essentially does the same thing)
Remove everything but "timeout /t 5 /nobreak > NUL" from your script. The process should return with an error (1) if the timeout failed because it is the last command executed.