Runtime rt = Runtime.getRuntime();
Process pr = rt.exec("java -jar map.jar time.rel test.txt debug");
http://docs.oracle.com/javase/7/docs/api/java/lang/Runtime.html
Answer from kol on Stack OverflowRuntime rt = Runtime.getRuntime();
Process pr = rt.exec("java -jar map.jar time.rel test.txt debug");
http://docs.oracle.com/javase/7/docs/api/java/lang/Runtime.html
You can also watch the output like this:
final Process p = Runtime.getRuntime().exec("java -jar map.jar time.rel test.txt debug");
new Thread(new Runnable() {
public void run() {
BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = null;
try {
while ((line = input.readLine()) != null)
System.out.println(line);
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
p.waitFor();
And don't forget, if you are running a windows command, you need to put cmd /c in front of your command.
EDIT: And for bonus points, you can also use ProcessBuilder to pass input to a program:
String[] command = new String[] {
"choice",
"/C",
"YN",
"/M",
"\"Press Y if you're cool\""
};
String inputLine = "Y";
ProcessBuilder pb = new ProcessBuilder(command);
pb.redirectErrorStream(true);
Process p = pb.start();
BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(p.getOutputStream()));
writer.write(inputLine);
writer.newLine();
writer.close();
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
This will run the windows command choice /C YN /M "Press Y if you're cool" and respond with a Y. So, the output will be:
Press Y if you're cool [Y,N]?Y
Couple of things that are happening incorrectly here:
- We need to pass our command as string tokens to the exec() command
- We need to wait for the process to exit with process.waitFor() instead of sleeping, this will block the current thread so if you don't want that you need to execute this in another thread or use an ExecutorService.
- Advisable to check the output value of waitFor() to see if our command executed properly (value of 0) or not (any other value, typically a positive 1 in case of unsuccessful execution)
- Optionally (to see the output) we need to redirect the standard OUT and ERR somewhere, say print it to console(), though you could put it to a file some GUI window etc.
So at a minimum the following code should work:
Process process = Runtime.getRuntime().exec(new String[] {"cmd", "/c", "cd", "C:\\dev", "&&", "dir"});
int outputVal = process.waitFor();
boolean alive = process.isAlive();
System.out.format("alive %s, outputVal: %d\n",alive, outputVal);
Further suggestions:
- use ProcessBuilder instead of runTime.exec(), it allows more control and is the recommended way since JDK 1.5
- read the inputStream
So the code will look some thing like this:
List<String> cmdList = Arrays.asList("cmd", "/c", "cd", "C:\\dev", "&&", "dir");
ProcessBuilder pb = new ProcessBuilder(cmdList);
pb.redirectErrorStream(true); //redirect STD ERR to STD OUT
Process process = pb.start();
try (final BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream()))) {
String line = null;
while ((line = br.readLine()) != null) {
System.out.println("std-out-line: " + line);
}
}
int outputVal = process.waitFor();
System.out.format("outputVal: %d\n", outputVal);
Since waitFor() is a blocking call, you can execute this in a separate thread or using an executorService. Sample code here:
final StringBuffer outputSb = new StringBuffer();
ExecutorService executorService = null;
try {
executorService = Executors.newSingleThreadExecutor();
final Future<Integer> future = executorService.submit(new Callable<Integer>() {
@Override
public Integer call() throws Exception {
try (final BufferedReader br = new BufferedReader(
new InputStreamReader(process.getInputStream()))) {
String line = null;
while ((line = br.readLine()) != null) {
outputSb.append("std-out-line: ");
outputSb.append(line);
outputSb.append('\n');
}
}
int exitValue = process.waitFor();
System.out.format("exitValue: %d\n", exitValue);
return exitValue;
}
});
while (!future.isDone()) {
System.out.println("Waiting for command to finish doing something else..");
Thread.sleep(1 * 1000);
}
int exitValue = future.get();
System.out.println("Output: " + outputSb);
} finally {
executorService.shutdown();
}
Here's a solution that uses WMIC.
public static void main( String[] args ) throws Exception {
// Vars
Process process;
String output;
// Execution
process = Runtime.getRuntime().exec("cmd /c wmic process call create calc.exe | findstr ProcessId");
output = readTrimmedOutput(process.getInputStream());
System.out.println("Output from command: " + output);
// Basic string manipulation to get process id
String str_proc_id = output.split(" = ")[1].replace(";","");
System.out.println("ProcessId is: " + str_proc_id);
// Some thread delay that you can comment/uncomment for testing if running or not
Thread.sleep(5000);
// Finding if process is still running
process = Runtime.getRuntime().exec("cmd /c wmic process get processid | findstr " + str_proc_id);
output = readTrimmedOutput(process.getInputStream());
boolean isRunning = output.contains(str_proc_id);
System.out.println("Is process still running? " + isRunning);
}
private static String readTrimmedOutput(InputStream is) throws Exception {
BufferedReader breader = new BufferedReader(new InputStreamReader(is));
String line = breader.readLine();
return line != null ? line.trim() : "";
}
Sample output
Output from command: ProcessId = 6480;
ProcessId is: 6480
Is process still running? true
For showing/displaying cmd console change some lines to:
// Execution
String your_command = "cmd.exe /c \"dir\"";
process = Runtime.getRuntime().exec("cmd /c wmic process call create \"" + your_command + "\" | findstr ProcessId");
References:
https://msdn.microsoft.com/en-us/library/aa394531(v=vs.85).aspx
https://www.computerhope.com/wmic.htm
One way to run a process from a different directory to the working directory of your Java program is to change directory and then run the process in the same command line. You can do this by getting cmd.exe to run a command line such as cd some_directory && some_program.
The following example changes to a different directory and runs dir from there. Admittedly, I could just dir that directory without needing to cd to it, but this is only an example:
Copyimport java.io.*;
public class CmdTest {
public static void main(String[] args) throws Exception {
ProcessBuilder builder = new ProcessBuilder(
"cmd.exe", "/c", "cd \"C:\\Program Files\\Microsoft SQL Server\" && dir");
builder.redirectErrorStream(true);
Process p = builder.start();
BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line;
while (true) {
line = r.readLine();
if (line == null) { break; }
System.out.println(line);
}
}
}
Note also that I'm using a ProcessBuilder to run the command. Amongst other things, this allows me to redirect the process's standard error into its standard output, by calling redirectErrorStream(true). Doing so gives me only one stream to read from.
This gives me the following output on my machine:
C:\Users\Luke\StackOverflow>java CmdTest
Volume in drive C is Windows7
Volume Serial Number is D8F0-C934
Directory of C:\Program Files\Microsoft SQL Server
29/07/2011 11:03 <DIR> .
29/07/2011 11:03 <DIR> ..
21/01/2011 20:37 <DIR> 100
21/01/2011 20:35 <DIR> 80
21/01/2011 20:35 <DIR> 90
21/01/2011 20:39 <DIR> MSSQL10_50.SQLEXPRESS
0 File(s) 0 bytes
6 Dir(s) 209,496,424,448 bytes free
You can try this:-
CopyProcess p = Runtime.getRuntime().exec(command);
