error in build to process builder in java - perl

Question

I have devloped myself tagger and I want to host on the web. my server is based on jsp. But This tagger is based on svmtool and it has been written in Perl script. That's why, I have created one ".java" file. In this file I've created Processor builder and via the Runtime.getRuntime().exec through this process I am calling this file. It is working but it doesn't show my output. Plz help to solve this issue. For the better under standing below I am giving my java code and also given last line of output/stop the process:
import java.io.*;
public class ExeCommand { String outS = "", errS="";
try {
// run the Unix "type your terminal command" command
System.out.println ("Running tagger!");
String command = "perl /home/svmtool_v1.3.2/bin/SVMTagger.pl -V 4 -S LRL /home/svmtool_v1.3.2/models/ih/IN < /home/tomcat4.1.40/webapps/pos/textfile/tests.txt > /home/tomcat4.1.40/webapps/pos/textfile/output.txt"; Process p = Runtime.getRuntime().exec(command);
BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));
// read the output from the command
System.out.println("It will take time so keep the patience:\n" + command);
System.out.println ("First error line: " + stdError.readLine());
// read any errors from the attempted command
System.out.println("Please check your command (if any):\n");
while ((errS = stdError.readLine()) != null) {
System.out.println("Error:\t" + errS);
}
stdError.close();
System.out.println ("First output line: " + stdInput.readLine());
while ((outS = stdInput.readLine()) != null) {
System.out.println("Output:\t" + outS);
}
stdInput.close();
System.out.println("Finished!");
}
catch (Exception e) {
System.out.println("found exception: " + e);
e.printStackTrace();
//System.exit(-1);
}
System.out.println("Finished all!");
}
}
After this nothing doing/ last output shows in terminal:
TAGGING < DIRECTION = left-to-right then right-to-left >

Answer 1

First, your perl script redirects its standard output to a file (
/home/tomcat4.1.40/webapps/pos/textfile/output.txt). So there is no way, you can capture standard output in Java.
Instead, you can use tee command which can write the output to both your output file and the standard output. Now, this can be captured in Java.
Second, use ProcessBuilder instead of Runtime. Process Builder is more flexible and gives you options to capture the standard output / input / error.
ProcessBuilder p = new ProcessBuilder();
p.inheritIO(); // Sets the source and destination for subprocess standard I/O to be the same as those of the current Java process.
p.command("perl", "somescript.pl");
p.start();

Answer 2

As I wrote here:
Sorry for the harsh words, but your code is a disaster. No compiler do something with it.
I have made no further tweaks to your code, I have the code modified so that it works at least:
package stackoverflow;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class ExeCommand {
/**
*
* run the Unix "type your terminal command" command
*
* #param args
*/
public static void main(String[] args) {
System.out.println("Running tagger!");
String command = "perl /home/svmtool_v1.3.2/bin/SVMTagger.pl -V 4 -S LRL /home/svmtool_v1.3.2/models/ih/IN < /home/tomcat4.1.40/webapps/pos/textfile/tests.txt > /home/tomcat4.1.40/webapps/pos/textfile/output.txt";
// String command = "ls -og";
Process p = null;
try {
p = Runtime.getRuntime().exec(command);
} catch (IOException e) {
e.printStackTrace();
}
// read the output from the command
System.out.println("It will take time so keep the patience:\n" + command);
BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));
try {
System.out.println(": " + stdError.readLine());
} catch (IOException e) {
e.printStackTrace();
}
// read any errors from the attempted command
System.out.println("Please check your command (if any):\n");
try {
String errS = "";
while ((errS = stdError.readLine()) != null) {
System.out.println("Error:\t" + errS);
}
} catch (IOException e) {
e.printStackTrace();
}
try {
stdError.close();
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
try {
System.out.println("First output line: " + stdInput.readLine());
} catch (IOException e) {
e.printStackTrace();
}
try {
String outS = "";
while ((outS = stdInput.readLine()) != null) {
System.out.println("Output:\t" + outS);
}
} catch (IOException e) {
e.printStackTrace();
}
try {
stdInput.close();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("Finished!");
}
}
Replace the lines 19 and 20
String command = "perl /home/svmtool_v1.3.2/bin/SVMTagger.pl -V 4 -S LRL /home/svmtool_v1.3.2/models/ih/IN < /home/tomcat4.1.40/webapps/pos/textfile/tests.txt > /home/tomcat4.1.40/webapps/pos/textfile/output.txt";
// String command = "ls -og";
with
// String command = "perl /home/svmtool_v1.3.2/bin/SVMTagger.pl -V 4 -S LRL /home/svmtool_v1.3.2/models/ih/IN < /home/tomcat4.1.40/webapps/pos/textfile/tests.txt > /home/tomcat4.1.40/webapps/pos/textfile/output.txt";
String command = "ls -og";
Then you get this output:
Running tagger!
It will take time so keep the patience:
ls -og
: null
Please check your command (if any):
First output line: insgesamt 12
Output: drwxrwxr-x 3 4096 Mai 23 20:51 bin
Output: drwxrwxr-x 3 4096 Apr 26 15:49 src
Output: -rw-rw-r-- 1 28 Apr 26 15:51 test
Finished!