I have a (Windows) command-line application that, when launched, prompts you to enter a password and then prints some text. Unfortunately, I do not own the source to the application and the application does not take any arguments when you launch it (i.e., cannot pass the password in when you start the application). I need to programmatically launch the application in Java and send a password to it and then read the response. While I have had success launching other programs (that just have output), I cannot seem to capture any output from this application. Here is my Java code:
import java.io.IOException;
import java.io.InputStream;
import java.lang.ProcessBuilder.Redirect;
public class RunCommand {
public static void main(String[] args) throws Exception {
new RunCommand().go();
}
void go() throws Exception {
ProcessBuilder pb = new ProcessBuilder("executable.exe");
pb.redirectErrorStream(true); // tried many combinations of these redirects and none seemed to help
pb.redirectInput(Redirect.INHERIT);
pb.redirectOutput(Redirect.INHERIT);
pb.redirectError(Redirect.INHERIT);
Process process = pb.start();
final Thread reader = new Thread(new Runnable() {
#Override
public void run() {
try {
final InputStream is = process.getInputStream();
int c;
while ((c = is.read()) != -1) {
// never gets here because c is always = -1
System.out.println((char) c);
}
} catch (IOException e) {
e.printStackTrace();
}
}
});
reader.start();
boolean cont = true;
while (cont) {
// force this to continue so we can try and get something from the input stream
}
process.destroyForcibly();
}
}
Related
This is my main class, wherein run(), I am calling one another method install setup() which is for exe files.
public static void main(String[] args) {
launch(args);
}
public void startSetup() {
Runnable task=new Runnable() {
#Override
public void run() {
try {
Thread.sleep(1000);
installSetup();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
Thread thread=new Thread(task);
thread.start();
}
Here is my installsetup() method
public void installSetup() {
try {
Runtime.getRuntime().exec("cmd /c C:path\\setup.exe", null, new File("C:pathfolder\\01_Setupexe"));
//process.waitFor();
} catch (IOException e) {
e.printStackTrace();
}
};
I am calling it in my controller class like this:
public class Controller extends Thread {
#FXML
private ComboBox<?> dsetup;
public void generateRandom() {
if(dsetup.getValue()!=null) dsetupValue = dsetup.getValue().toString();
if(dsetupValue!=null)call.startSetup();
Before I was just calling the install files with the exec method but not with threads concept, the application was working fine, but it was executing all the.exe files at once and then my interface freezes. So now I am using threads concept and trying to implement one thread at a time. I don't understand if it is a wrong way or not, but I do not get any error in console.
Runtime.exec has been obsolete for many years. Use ProcessBuilder instead:
ProcessBuilder builder = new ProcessBuilder("C:\\path\\setup.exe");
builder.directory(new File("C:pathfolder\\01_Setupexe"));
builder.inheritIO();
builder.start();
The inheritIO() method will make the spawned process use the Java program’s stdin, stdout, and stderr, so it will not hang waiting for input or waiting for an available output buffer.
I doubt you need the new Thread or the sleep call, but I don’t know what files you’re calling or whether they depend on each other.
Sadly exec has some pitfalls. Most of the time using the process aproche (see Listing 4.3) saved me related to buffer issues and so on.
https://www.javaworld.com/article/2071275/core-java/when-runtime-exec---won-t.html
import java.util.*;
import java.io.*;
public class MediocreExecJavac
{
public static void main(String args[])
{
try
{
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec("javac");
InputStream stderr = proc.getErrorStream();
InputStreamReader isr = new InputStreamReader(stderr);
BufferedReader br = new BufferedReader(isr);
String line = null;
System.out.println("<ERROR>");
while ( (line = br.readLine()) != null)
System.out.println(line);
System.out.println("</ERROR>");
int exitVal = proc.waitFor();
System.out.println("Process exitValue: " + exitVal);
} catch (Throwable t)
{
t.printStackTrace();
}
}
}
Source: javaworld
My requirement is to start a process from java and register for events callback for the process for eg: like started or killed.
Typical scenario:
In my GUI application, I have a "start process" button with "start/running" status text. I want the status to dynamically change when the process is running or not running.
I don't want to continuously check for the list of process and query for my process but a way the callback is triggered when the process is completed.
Quick and unrefined solution - Java8 - (just in case, for the unaware: see java.lang.Process and java.lang.ProcessBuilder on how to start one)
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
public class ProcessObserver
implements Runnable {
protected Consumer<Process> callback;
protected Process toExecute;
public ProcessObserver(
Consumer<Process> callback,
Process toExecute
) {
super();
this.callback = callback;
this.toExecute = toExecute;
}
#Override
public void run() {
while(this.toExecute.isAlive()) {
try {
this.toExecute.waitFor(250, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
this.toExecute.destroyForcibly();
return; // Honouring the interrupt request,
// bail out here and don call the callback
}
}
this.callback.accept(this.toExecute);
}
static public void main(String[] args) {
ThreadPoolExecutor pool=new ThreadPoolExecutor(
4, 1024, // the threads will mostly sleep in waitFors
3600, TimeUnit.SECONDS,
new LinkedBlockingQueue<Runnable>()
);
Process longRunningProcess=null; // initialize it properly
ProcessObserver observer=new ProcessObserver(
(Process p)->System.out.println("Exit code of: "+p.exitValue()),
longRunningProcess
);
pool.execute(observer);
}
}
A more refined solution will involve a single thread monitoring multiple processes polling them periodically and invoking the associated callback for those that exited (after all, a 0.2s-1s delay in reporting the exit code for long running processes won't make too much of a difference).
You can try something similar to this:
public interface Callback{
public void executeCallbackActions();
}
public static void main(String[] args) {
Callback callback = new Callback() {
#Override
public void executeCallbackActions() {
System.out.println("Who pressed the button?");
}
};
runGui(callback);
}
public static void runGui(Callback callback){
//When button is pressed
callback.executeCallbackActions();
}
you can use processbuilder like below
public class ProcessBuildDemo {
public static void processdone() {
System.out.println("processing is done....");
}
public static void main(String[] args) throws IOException {
String[] command = {"notepad.exe"};
ProcessBuilder probuilder = new ProcessBuilder( command );
Process process = probuilder.start();
//
// set status of you button as process is runnning
//Read out dir output
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
System.out.printf("Output of running %s is:\n",
Arrays.toString(command));
while ((line = br.readLine()) != null) {
System.out.println(line);
}
//Wait to get exit value
try {
int exitValue = process.waitFor();
//set status of you button as process is stop or do call function
processdone();
System.out.println("\n\nExit Value is " + exitValue);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
I am trying to create a sort of console/terminal that allows the user to input a string, which then gets made into a process and the results are printed out. Just like a normal console. But I am having trouble managing the input/output streams. I have looked into this thread, but that solution sadly doesn't apply to my problem.
Along with the standard commands like "ipconfig" and "cmd.exe", I need to be able to run a script and use the same inputstream to pass some arguments, if the script is asking for input.
For example, after running a script "python pyScript.py", I should be able pass further input to the script if it is asking for it(example: raw_input), while also printing the output from the script. The basic behavior you would expect from a terminal.
What I've got so far:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
public class Console extends JFrame{
JTextPane inPane, outPane;
InputStream inStream, inErrStream;
OutputStream outStream;
public Console(){
super("Console");
setPreferredSize(new Dimension(500, 600));
setLocationByPlatform(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// GUI
outPane = new JTextPane();
outPane.setEditable(false);
outPane.setBackground(new Color(20, 20, 20));
outPane.setForeground(Color.white);
inPane = new JTextPane();
inPane.setBackground(new Color(40, 40, 40));
inPane.setForeground(Color.white);
inPane.setCaretColor(Color.white);
JPanel panel = new JPanel(new BorderLayout());
panel.add(outPane, BorderLayout.CENTER);
panel.add(inPane, BorderLayout.SOUTH);
JScrollPane scrollPanel = new JScrollPane(panel);
getContentPane().add(scrollPanel);
// LISTENER
inPane.addKeyListener(new KeyListener(){
#Override
public void keyPressed(KeyEvent e){
if(e.getKeyCode() == KeyEvent.VK_ENTER){
e.consume();
read(inPane.getText());
}
}
#Override
public void keyTyped(KeyEvent e) {}
#Override
public void keyReleased(KeyEvent e) {}
});
pack();
setVisible(true);
}
private void read(String command){
println(command);
// Write to Process
if (outStream != null) {
System.out.println("Outstream again");
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outStream));
try {
writer.write(command);
//writer.flush();
//writer.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
// Execute Command
try {
exec(command);
} catch (IOException e) {}
inPane.setText("");
}
private void exec(String command) throws IOException{
Process pro = Runtime.getRuntime().exec(command, null);
inStream = pro.getInputStream();
inErrStream = pro.getErrorStream();
outStream = pro.getOutputStream();
Thread t1 = new Thread(new Runnable() {
public void run() {
try {
String line = null;
while(true){
BufferedReader in = new BufferedReader(new InputStreamReader(inStream));
while ((line = in.readLine()) != null) {
println(line);
}
BufferedReader inErr = new BufferedReader(new InputStreamReader(inErrStream));
while ((line = inErr.readLine()) != null) {
println(line);
}
Thread.sleep(1000);
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
t1.start();
}
public void println(String line) {
Document doc = outPane.getDocument();
try {
doc.insertString(doc.getLength(), line + "\n", null);
} catch (BadLocationException e) {}
}
public static void main(String[] args){
new Console();
}
}
I don't use the mentioned ProcessBuilder, since I do like to differentiate between error and normal stream.
UPDATE 29.08.2016
With the help of #ArcticLord we have achieved what was asked in the original question.
Now it is just a matter of ironing out any strange behavior like the non terminating process. The Console has a "stop" button that simply calls pro.destroy(). But for some reason this does not work for infinitely running processes, that are spamming outputs.
Console: http://pastebin.com/vyxfPEXC
InputStreamLineBuffer: http://pastebin.com/TzFamwZ1
Example code that does not stop:
public class Infinity{
public static void main(String[] args){
while(true){
System.out.println(".");
}
}
}
Example code that does stop:
import java.util.concurrent.TimeUnit;
public class InfinitySlow{
public static void main(String[] args){
while(true){
try {
TimeUnit.SECONDS.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(".");
}
}
}
You are on the right way with your code. There are only some minor things you missed.
Lets start with your read method:
private void read(String command){
[...]
// Write to Process
if (outStream != null) {
[...]
try {
writer.write(command + "\n"); // add newline so your input will get proceed
writer.flush(); // flush your input to your process
} catch (IOException e1) {
e1.printStackTrace();
}
}
// ELSE!! - if no outputstream is available
// Execute Command
else {
try {
exec(command);
} catch (IOException e) {
// Handle the exception here. Mostly this means
// that the command could not get executed
// because command was not found.
println("Command not found: " + command);
}
}
inPane.setText("");
}
Now lets fix your exec method. You should use separate threads for reading normal process output and error output. Additionally I introduce a third thread that waits for the process to end and closes the outputStream so next user input is not meant for process but is a new command.
private void exec(String command) throws IOException{
Process pro = Runtime.getRuntime().exec(command, null);
inStream = pro.getInputStream();
inErrStream = pro.getErrorStream();
outStream = pro.getOutputStream();
// Thread that reads process output
Thread outStreamReader = new Thread(new Runnable() {
public void run() {
try {
String line = null;
BufferedReader in = new BufferedReader(new InputStreamReader(inStream));
while ((line = in.readLine()) != null) {
println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("Exit reading process output");
}
});
outStreamReader.start();
// Thread that reads process error output
Thread errStreamReader = new Thread(new Runnable() {
public void run() {
try {
String line = null;
BufferedReader inErr = new BufferedReader(new InputStreamReader(inErrStream));
while ((line = inErr.readLine()) != null) {
println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("Exit reading error stream");
}
});
errStreamReader.start();
// Thread that waits for process to end
Thread exitWaiter = new Thread(new Runnable() {
public void run() {
try {
int retValue = pro.waitFor();
println("Command exit with return value " + retValue);
// close outStream
outStream.close();
outStream = null;
} catch (InterruptedException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
});
exitWaiter.start();
}
Now this should work.
If you enter ipconfig it prints the command output, closes the output stream and is ready for a new command.
If you enter cmd it prints the output and let you enter more cmd commands like dir or cd and so on until you enter exit. Then it closes the output stream and is ready for a new command.
You may run into problems with executing python scripts because there are problems with reading Process InputStreams with Java if they are not flushed into system pipeline.
See this example python script
print "Input something!"
str = raw_input()
print "Received input is : ", str
You could run this with your Java programm and also enter the input but you will not see the script output until the script is finished.
The only fix I could find is to manually flush the output in the script.
import sys
print "Input something!"
sys.stdout.flush()
str = raw_input()
print "Received input is : ", str
sys.stdout.flush()
Running this script will bahave as you expect.
You can read more about this problem at
Java: is there a way to run a system command and print the output during execution?
Why does reading from Process' InputStream block altough data is available
Java: can't get stdout data from Process unless its manually flushed
EDIT: I have just found another very easy solution for the stdout.flush() problem with Python Scripts. Start them with python -u script.py and you don't need to flush manually. This should solve your problem.
EDIT2: We discussed in the comments that with this solution output and error Stream will be mixed up since they run in different threads. The problem here is that we cannot distinguish if output writing is finish when error stream thread comes up. Otherwise classic thread scheduling with locks could handle this situation. But we have a continuous stream until process is finished no matter if data flows or not. So we need a mechanism here that logs how much time has elapsed since last line was read from each stream.
For this I will introduce a class that gets an InputStream and starts a Thread for reading the incoming data. This Thread stores each line in a Queue and stops when end of stream arrives. Additionally it holds the time when last line was read and added to Queue.
public class InputStreamLineBuffer{
private InputStream inputStream;
private ConcurrentLinkedQueue<String> lines;
private long lastTimeModified;
private Thread inputCatcher;
private boolean isAlive;
public InputStreamLineBuffer(InputStream is){
inputStream = is;
lines = new ConcurrentLinkedQueue<String>();
lastTimeModified = System.currentTimeMillis();
isAlive = false;
inputCatcher = new Thread(new Runnable(){
#Override
public void run() {
StringBuilder sb = new StringBuilder(100);
int b;
try{
while ((b = inputStream.read()) != -1){
// read one char
if((char)b == '\n'){
// new Line -> add to queue
lines.offer(sb.toString());
sb.setLength(0); // reset StringBuilder
lastTimeModified = System.currentTimeMillis();
}
else sb.append((char)b); // append char to stringbuilder
}
} catch (IOException e){
e.printStackTrace();
} finally {
isAlive = false;
}
}});
}
// is the input reader thread alive
public boolean isAlive(){
return isAlive;
}
// start the input reader thread
public void start(){
isAlive = true;
inputCatcher.start();
}
// has Queue some lines
public boolean hasNext(){
return lines.size() > 0;
}
// get next line from Queue
public String getNext(){
return lines.poll();
}
// how much time has elapsed since last line was read
public long timeElapsed(){
return (System.currentTimeMillis() - lastTimeModified);
}
}
With this class we could combine the output and error reading thread into one. That lives while the input reading buffer threads live and have not comsumed data. In each run it checks if some time has passed since last output was read and if so it prints all unprinted lines at a stroke. The same with the error output. Then it sleeps for some millis for not wasting cpu time.
private void exec(String command) throws IOException{
Process pro = Runtime.getRuntime().exec(command, null);
inStream = pro.getInputStream();
inErrStream = pro.getErrorStream();
outStream = pro.getOutputStream();
InputStreamLineBuffer outBuff = new InputStreamLineBuffer(inStream);
InputStreamLineBuffer errBuff = new InputStreamLineBuffer(inErrStream);
Thread streamReader = new Thread(new Runnable() {
public void run() {
// start the input reader buffer threads
outBuff.start();
errBuff.start();
// while an input reader buffer thread is alive
// or there are unconsumed data left
while(outBuff.isAlive() || outBuff.hasNext() ||
errBuff.isAlive() || errBuff.hasNext()){
// get the normal output if at least 50 millis have passed
if(outBuff.timeElapsed() > 50)
while(outBuff.hasNext())
println(outBuff.getNext());
// get the error output if at least 50 millis have passed
if(errBuff.timeElapsed() > 50)
while(errBuff.hasNext())
println(errBuff.getNext());
// sleep a bit bofore next run
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("Finish reading error and output stream");
}
});
streamReader.start();
// remove outStreamReader and errStreamReader Thread
[...]
}
Maybe this is not a perfect solution but it should handle the situation here.
EDIT (31.8.2016)
We discussed in comments that there is still a problem with the code while implementing a stop button that kills the started
process using Process#destroy(). A process that produces very much output e.g. in an infinite loop will
be destroyed immediately by calling destroy(). But since it has already produced a lot of output that has to be consumed
by our streamReader we can't get back to normal programm behaviour.
So we need some small changes here:
We will introduce a destroy() method to the InputStreamLineBuffer that stops the output reading and clears the queue.
The changes will look like this:
public class InputStreamLineBuffer{
private boolean emergencyBrake = false;
[...]
public InputStreamLineBuffer(InputStream is){
[...]
while ((b = inputStream.read()) != -1 && !emergencyBrake){
[...]
}
}
[...]
// exits immediately and clears line buffer
public void destroy(){
emergencyBrake = true;
lines.clear();
}
}
And some little changes in the main programm
public class ExeConsole extends JFrame{
[...]
// The line buffers must be declared outside the method
InputStreamLineBuffer outBuff, errBuff;
public ExeConsole{
[...]
btnStop.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(pro != null){
pro.destroy();
outBuff.destroy();
errBuff.destroy();
}
}});
}
[...]
private void exec(String command) throws IOException{
[...]
//InputStreamLineBuffer outBuff = new InputStreamLineBuffer(inStream);
//InputStreamLineBuffer errBuff = new InputStreamLineBuffer(inErrStream);
outBuff = new InputStreamLineBuffer(inStream);
errBuff = new InputStreamLineBuffer(inErrStream);
[...]
}
}
Now it should be able to destroy even some output spamming processes.
Note: I found out that Process#destroy() is not able to destroy child processes. So if you start cmd on windows
and start a java programm from there you will end up destroying the cmd process while the java programm is still running.
You will see it in the task manager. This problem could not be solved with java itself. it will need
some os depending external tools to get the pids of these processes and kill them manually.
Although #ArticLord solution is nice and neat, recently I faced the same kind of problem and came up with a solution that's conceptually equivalent, but slightly different in its implementation.
The concept is the same, namely "bulk reads": when a reader thread acquires its turn, it consumes all the stream it handles, and pass the hand only when it is done.
This guarantees the out/err print order.
But instead of using a timer-based turn assignment, I use a lock-based non-blocking read simulation:
// main method for testability: replace with private void exec(String command)
public static void main(String[] args) throws Exception
{
// create a lock that will be shared between reader threads
// the lock is fair to minimize starvation possibilities
ReentrantLock lock = new ReentrantLock(true);
// exec the command: I use nslookup for testing on windows
// because it is interactive and prints to stderr too
Process p = Runtime.getRuntime().exec("nslookup");
// create a thread to handle output from process (uses a test consumer)
Thread outThread = createThread(p.getInputStream(), lock, System.out::print);
outThread.setName("outThread");
outThread.start();
// create a thread to handle error from process (test consumer, again)
Thread errThread = createThread(p.getErrorStream(), lock, System.err::print);
errThread.setName("errThread");
errThread.start();
// create a thread to handle input to process (read from stdin for testing purpose)
PrintWriter writer = new PrintWriter(p.getOutputStream());
Thread inThread = createThread(System.in, null, str ->
{
writer.print(str);
writer.flush();
});
inThread.setName("inThread");
inThread.start();
// create a thread to handle termination gracefully. Not really needed in this simple
// scenario, but on a real application we don't want to block the UI until process dies
Thread endThread = new Thread(() ->
{
try
{
// wait until process is done
p.waitFor();
logger.debug("process exit");
// signal threads to exit
outThread.interrupt();
errThread.interrupt();
inThread.interrupt();
// close process streams
p.getOutputStream().close();
p.getInputStream().close();
p.getErrorStream().close();
// wait for threads to exit
outThread.join();
errThread.join();
inThread.join();
logger.debug("exit");
}
catch(Exception e)
{
throw new RuntimeException(e.getMessage(), e);
}
});
endThread.setName("endThread");
endThread.start();
// wait for full termination (process and related threads by cascade joins)
endThread.join();
logger.debug("END");
}
// convenience method to create a specific reader thread with exclusion by lock behavior
private static Thread createThread(InputStream input, ReentrantLock lock, Consumer<String> consumer)
{
return new Thread(() ->
{
// wrap input to be buffered (enables ready()) and to read chars
// using explicit encoding may be relevant in some case
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
// create a char buffer for reading
char[] buffer = new char[8192];
try
{
// repeat until EOF or interruption
while(true)
{
try
{
// wait for your turn to bulk read
if(lock != null && !lock.isHeldByCurrentThread())
{
lock.lockInterruptibly();
}
// when there's nothing to read, pass the hand (bulk read ended)
if(!reader.ready())
{
if(lock != null)
{
lock.unlock();
}
// this enables a soft busy-waiting loop, that simultates non-blocking reads
Thread.sleep(100);
continue;
}
// perform the read, as we are sure it will not block (input is "ready")
int len = reader.read(buffer);
if(len == -1)
{
return;
}
// transform to string an let consumer consume it
String str = new String(buffer, 0, len);
consumer.accept(str);
}
catch(InterruptedException e)
{
// catch interruptions either when sleeping and waiting for lock
// and restore interrupted flag (not necessary in this case, however it's a best practice)
Thread.currentThread().interrupt();
return;
}
catch(IOException e)
{
throw new RuntimeException(e.getMessage(), e);
}
}
}
finally
{
// protect the lock against unhandled exceptions
if(lock != null && lock.isHeldByCurrentThread())
{
lock.unlock();
}
logger.debug("exit");
}
});
}
Note that both solutions, #ArticLord's and mine, are not totally starvation-safe, and chances (really few) are inversely proportional to consumers speed.
Happy 2016! ;)
I'm working on a project and I would like to execute programs in the windows console or a linux terminal.
Instead of launching a new console and working the program in it I want to do something like the following:
rt.exec("cmd.exe /c start cmd.exe /k ruby rubycode.rb");
From this point on I want the user to be able to work with the program from the GUI/my program. The idea in my min is starting cmd in silent mode where it is not visible and latching on to it. Then redirecting the console output to the GUI and letting the user input data to the console through the GUI.
A similar concept is what most IDEs like jgrasp do. When you run a program you interface with it though their own command prompt.
How is this done? Iv'e tried grabbing the IOStreams from the process and trying to atleast print what the console outputs but no luck.
Here is an example:
public class ProcessTest {
private Process p;
private BufferedReader reader;
private BufferedWriter writer;
public void start() throws IOException {
ProcessBuilder pb = new ProcessBuilder("cmd", "/c", "dir");
pb.directory(new File("./"));
this.p = pb.start();
this.reader = new BufferedReader(new InputStreamReader(this.p.getInputStream()));
this.writer = new BufferedWriter(new OutputStreamWriter(this.p.getOutputStream()));
new Read(this.reader).start();
}
public boolean writeToConsole(String s) throws IOException {
if (p == null)
return false;
this.writer.write(s + "\n");
this.writer.flush();
return true;
}
public class Read extends Thread {
private BufferedReader reader;
public Read(BufferedReader reader) {
this.reader = reader;
}
public void run() {
try {
String line;
while ((line = this.reader.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
try {
new ProcessTest().start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
With the writeToConsole method you can write any string to the programm that you executed.
I'm writing a program that will run continuously and I was wondering if there was a Java equivalent to the Autoit SetHotKey(Key, Action()). I saw an answer on here that related to a GUI interface, but my program does not have a GUI. I just want the program to exit whenever I press a certain key, preferably ESC.
I'd have the program running in an infinite loop using the awt.Robot's keyevents, I'd like to be able to quit the program by pressing a certain key.
There are no core Java solutions since Java was built to be as operating system agnostic as possible, and to achieve your goal, you need a program that can integrate closer to the OS. The main solutions that I know of are to integrate your program to the OS via JNA, JNI, or (my favorite), AutoIt. Of done something similar by simply having my Java program and AutoIt communicate through standard IO and sockets.
A simple example:
Java program, TrialAutoIt3a.java:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Scanner;
public class TrialAutoIt3a {
// ***** of course your path to program will be different
private static final String AUTOIT_PATH = "C:/Users/Pete/Documents/Programming/AutoIt/Experiment/";
private static final String AUTOIT_EXEC = "TestWithJava.exe";
protected static final CharSequence EXIT = "exit";
private static Process proc = null;
public static void main(String[] args) {
Runtime rt = Runtime.getRuntime();
System.out.println("Type \"exit\" to exit program");
try {
proc = rt.exec(AUTOIT_PATH + AUTOIT_EXEC);
} catch (IOException e1) {
e1.printStackTrace();
System.exit(-1);
}
InputStream iStream = proc.getInputStream();
InputStreamReader isr = new InputStreamReader(iStream);
final BufferedReader bufReader = new BufferedReader(isr);
OutputStream oStream = proc.getOutputStream();
final PrintWriter pw = new PrintWriter(oStream, true);
Runnable bufReaderRunnable = new Runnable() {
public void run() {
String output;
try {
while ((output = bufReader.readLine()) != null) {
System.out.println(output);
if (output.toLowerCase().contains(EXIT)) {
proc.destroy();
System.exit(0);
}
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (bufReader != null) {
try {
bufReader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
};
new Thread(bufReaderRunnable).start();
Runnable myRun = new Runnable() {
public void run() {
Scanner scan = new Scanner(System.in);
while (scan.hasNextLine()) {
String line = scan.nextLine();
pw.println(line);
}
scan.close();
}
};
new Thread(myRun).start();
}
}
AutoIt program, TestWithJava.au3:
Local $line = ""
While (True)
$line = $line & ConsoleRead()
If StringInStr($line, #CR) Or StringInStr($line, #LF) Then
ConsoleWrite($line & "to java" & #CRLF)
$line = ""
EndIf
Sleep(25)
WEnd
The AutoIt program will be compiled to an exe file prior to running this program