I'm trying to run a python script during the execution of my java code, because it will depend on the output received from the python script. So far I've tried using jythonc, unfortunately to no success, and now im trying to use the java Runtime and java Process to execute the python script.
Now I've run into a problem when trying to call the python script. I feel as though it doesn't even call the script because it takes less than a couple seconds to get to the next page....
Could the problem be how I am calling the python script?? I am trying to run this through a web application...
Here is some of my code:
String run = "cmd /c python duplicatetestingoriginal.py" ;
boolean isCreated = fwr.writeFile(BugFile, GD, 500, true, 5, "LET");
if(isCreated){
try{
r = Runtime.getRuntime();
p = r.exec(run);
BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));
String line = "";
while ((line = stdInput.readLine()) != null) {
System.out.println(line);
}
while ((line = stdError.readLine()) != null) {
errorW.write(line);
}
int exitVal = p.waitFor();
arrayList = fwr.readResults();
}catch(Exception e){
}
}
else{
// troubleshoot....
}
Instead of String for the command, split it to chunks and make a String[]. No need to state cmd /c, I think.
This is a sample code from my application:
//Running on windows
command = new String[4];
command[0]=directory.getCanonicalPath()+"/data/ExtenalApp.exe"; //extenal commandline app, not placed in path, but in subfolder
command[1]=directory.getCanonicalPath()+"/data/SomeFile.txt"; //file needed for the external app, sent as an argument
command[2]=arg1; //argument for the app
command[3]=arg2; //argument for the app
//Running on Mac
command = new String[6];
command[0]="python";
command[1]=directory.getCanonicalPath()+"/data/wp.py"; //path to the script
command[2]="-F"; //argument/Flag/option
command[3]="--dir="+path; //argument/option
command[4]="--filename="+filename; //argument/option
command[5]=argument; //argument/option
Process process = Runtime.getRuntime().exec(command);
process.waitFor();
process.destroy();
I don't handle the Input/Output streams because the script/app doesn't require input, and outputs only when finished, nothing important. Which might not be the case for you.
Related
I'm looking a way to write running log of python which is executed by java app via script.
Let's say my script is:
import time
for x in range(120):
print("Running ", x)
time.sleep(1)
Here is my current solution:
Trigger script using java
String cmd = "python script.py";
var process = Runtime.getRuntime().exec(cmd, null, new File(sandboxPath));
Write log to new file:
String traceLogCmd = String.format("strace -p %s -s 9999 -e trace=write -o output.txt", process.pid());
Runtime.getRuntime().exec(traceLogCmd, null, new File(sandboxPath));
Now the problem is output.txt only has content whenever the python script is done executing so that I cannot tailf the output file.
Meanwhile if I execute python script.py and strace command dirrectly from terminal, the output is exactly what I expected.
Can someone correct me if I did something wrong or have a another way to get python log?
Thanks in advance.
Use ProcessBuilder instead of Runtime.exec(). More details: When Runtime.exec() won't
The following code will append to StringBuilder object output of the script sb.append(line);. It would not be difficult to write that content to a file.
Process p = new ProcessBuilder("sh", "-c", "python", "path-to-your-script").start();
String result = getCommandResult(p.getInputStream());
private static String getCommandResult(InputStream stream) throws IOException {
StringBuilder sb = new StringBuilder();
try (InputStreamReader isr = new InputStreamReader(stream);
BufferedReader in = new BufferedReader(isr)) {
String line;
while ((line = in.readLine()) != null) {
sb.append(line);
}
}
return sb.toString().trim();
}
I can execute Linux commands like ls or pwd from Java without problems but couldn't get a Python script executed.
This is my code:
Process p;
try{
System.out.println("SEND");
String cmd = "/bash/bin -c echo password| python script.py '" + packet.toString() + "'";
//System.out.println(cmd);
p = Runtime.getRuntime().exec(cmd);
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String s = br.readLine();
System.out.println(s);
System.out.println("Sent");
p.waitFor();
p.destroy();
} catch (Exception e) {}
Nothing happened. It reached SEND but it just stopped after it...
I am trying to execute a script which needs root permissions because it uses serial port. Also, I have to pass a string with some parameters (packet).
You cannot use the PIPE inside the Runtime.getRuntime().exec() as you do in your example. PIPE is part of the shell.
You could do either
Put your command to a shell script and execute that shell script with .exec() or
You can do something similar to the following
String[] cmd = {
"/bin/bash",
"-c",
"echo password | python script.py '" + packet.toString() + "'"
};
Runtime.getRuntime().exec(cmd);
#Alper's answer should work. Better yet, though, don't use a shell script and redirection at all. You can write the password directly to the process' stdin using the (confusingly named) Process.getOutputStream().
Process p = Runtime.exec(
new String[]{"python", "script.py", packet.toString()});
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(p.getOutputStream()));
writer.write("password");
writer.newLine();
writer.close();
You would do worse than to try embedding jython and executing your script. A simple example should help:
ScriptEngine engine = new ScriptEngineManager().getEngineByName("python");
// Using the eval() method on the engine causes a direct
// interpretataion and execution of the code string passed into it
engine.eval("import sys");
engine.eval("print sys");
If you need further help, leave a comment. This does not create an additional process.
First, open terminal and type "which python3". You will get the complete path of python3. For example "/usr/local/bin/python3"
String[] cmd = {"/usr/local/bin/python3", "arg1", "arg2"};
Process p = Runtime.getRuntime().exec(cmd);
p.waitFor();
String line = "", output = "";
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((line = br.readLine())!= null) {sb = sb.append(line).append("\n"); }
output = sb.toString();
System.out.println(output);
I have a computer algebra program (called Reduce) that works in the shell in an interactive manner: launch Reduce in the shell, then you can define variables, compute this and that, and what not. Reduce prints the output into the shell. My idea is that I want to build a frontend for this text-based program that evaluates its output and converts it into a nice LaTeX style formula. For this I want to use Java.
I can start Reduce via exec(). But how can I emulate text input to the opened shell, and how can I read back what Reduce writes into the shell?
Thanks
Jens
Edit 1: Current Code
// get the shell
Runtime rt = Runtime.getRuntime();
// execute reduce
String[] commands = {"D:/Programme/Reduce/reduce.com", "", ""};
Process proc = null;
try {
proc = rt.exec(commands);
} catch (Exception e) {
System.out.println("Error!\n");
}
// get the associated input / output / error streams
BufferedReader stdInput = new BufferedReader(new InputStreamReader(proc.getInputStream()));
BufferedWriter stdOutput = new BufferedWriter(new OutputStreamWriter(proc.getOutputStream()));
BufferedReader stdError = new BufferedReader(new InputStreamReader(proc.getErrorStream()));
// read the output from the command
System.out.println("Here is the standard output of the command:\n");
String s = null;
try {
while ((s = stdInput.readLine()) != null) {
System.out.println(s);
}
} catch (Exception e) {
}
// read any errors from the attempted command
System.out.println("Here is the standard error of the command (if any):\n");
try {
while ((s = stdError.readLine()) != null) {
System.out.println(s);
}
} catch (Exception e) {
}
You need to get the streams associated with the process including the InputStream, OutputStream, and ErrorStream. You then can send messages to the process via the OutputStream and then read info from the process via the InputStream and the ErrorStream.
From some code of mine:
final ProcessBuilder pBuilder = new ProcessBuilder(TEST_PROCESS_ARRAY);
final Process proc = pBuilder.start();
procInputStream = proc.getInputStream();
errorStream = proc.getErrorStream();
errorSBuffer = new StringBuffer();
streamGobblerSb = new StreamGobblerSb(errorStream, "Autoit Error", errorSBuffer);
new Thread(streamGobblerSb).start();
final Scanner scan = new Scanner(procInputStream);
You may want to look into using the Process class.
http://docs.oracle.com/javase/7/docs/api/java/lang/Process.html
I believe you may be able to start the process, and then use getOutputStream() to feed commands into the process.
While this is not strictly an answer, I discovered that it is more convenient for me to stick with PHP's function proc_open(). That way I can include the output directly in the frontend and do not need to worry about the communication between my Java program and the html frontend.
For everybody who wants to stick to the Java method: the article http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html is a good reference.
I can execute Linux commands like ls or pwd from Java without problems but couldn't get a Python script executed.
This is my code:
Process p;
try{
System.out.println("SEND");
String cmd = "/bash/bin -c echo password| python script.py '" + packet.toString() + "'";
//System.out.println(cmd);
p = Runtime.getRuntime().exec(cmd);
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String s = br.readLine();
System.out.println(s);
System.out.println("Sent");
p.waitFor();
p.destroy();
} catch (Exception e) {}
Nothing happened. It reached SEND but it just stopped after it...
I am trying to execute a script which needs root permissions because it uses serial port. Also, I have to pass a string with some parameters (packet).
You cannot use the PIPE inside the Runtime.getRuntime().exec() as you do in your example. PIPE is part of the shell.
You could do either
Put your command to a shell script and execute that shell script with .exec() or
You can do something similar to the following
String[] cmd = {
"/bin/bash",
"-c",
"echo password | python script.py '" + packet.toString() + "'"
};
Runtime.getRuntime().exec(cmd);
#Alper's answer should work. Better yet, though, don't use a shell script and redirection at all. You can write the password directly to the process' stdin using the (confusingly named) Process.getOutputStream().
Process p = Runtime.exec(
new String[]{"python", "script.py", packet.toString()});
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(p.getOutputStream()));
writer.write("password");
writer.newLine();
writer.close();
You would do worse than to try embedding jython and executing your script. A simple example should help:
ScriptEngine engine = new ScriptEngineManager().getEngineByName("python");
// Using the eval() method on the engine causes a direct
// interpretataion and execution of the code string passed into it
engine.eval("import sys");
engine.eval("print sys");
If you need further help, leave a comment. This does not create an additional process.
First, open terminal and type "which python3". You will get the complete path of python3. For example "/usr/local/bin/python3"
String[] cmd = {"/usr/local/bin/python3", "arg1", "arg2"};
Process p = Runtime.getRuntime().exec(cmd);
p.waitFor();
String line = "", output = "";
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((line = br.readLine())!= null) {sb = sb.append(line).append("\n"); }
output = sb.toString();
System.out.println(output);
I used to write PHP code to execute pig command, it worked well,
Now I switch to Java but seems it won't work, here is my code:
String pigCommand = "pig -x local -p ouput=/tmp my_pig_script.pig";
Runtime r = Runtime.getRuntime();
Process p;
int exitVal;
try {
p = r.exec(pigCommand);
exitVal = p.waitFor();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = null;
while((line = br.readLine()) != null) {
System.out.println(line);
}
br.close();
System.out.println("exitVal: " + exitVal);
System.out.println("Done");
If I run the that pig command in console directly, it works, if I replace
that Pig command with other shell command say 'ping www.yahoo.com', and run the
java Program, it works too. So what might be the problem? thanks
You should use PigServer to execute pig scripts from java programs. It is more foolproof and more portable.
Also see this answer: https://stackoverflow.com/a/11299259/373151