Runtime.getRuntime().exec(s) spaces in s are trimed

[Xu Li]

I use Runtime.getRuntime().exec(s). s is passed as "cmd /c c:\\test.exe \"1 2\"", but the args[1] in the main of test.exe is changed to "1 2". What should I do to keep the space in the parameters that is essential. Pls. advice. Thx. a lot.

[Maulin Vasavada]

hi Xu,
u can use,
Process exec(String[] cmdarray)

method of Runtime instead of simple exec(String command) as per the API...
here this string array has the following format,
String[]{'command','arg1','arg2','arg3',...}
so this way you can separate arguments...
now u can use,
String[]{'command',"1 2"} in your case which should solve ur problem.
hope i got your question correctly. let me know if i've misunderstood ur question...
please look at the
API
for more details...
regards
maulin

[Michael Zalewski]

I bet it also works if you take out the cmd /c.
My guess is cmd sees the argument with the spaces. So it sees the arguments "/c", "c:\test.exe", and "1 2". It does its thing (specified by "/c", and builds the command "c:\test.exe 1 2".
If you really need to use cmd /c, try triple quoting. "cmd /c c:\\test.exe \"\"\"1 2\"\"\"". Now, cmd should see the arguments '/c', 'c:\test.exe', and '"1 2"'. So it should execute the command 'c:\test.exe "1 2"', which is what you want (I think).

[Xu Li]

Hi,
Thanks a lot for both of ur replies. I am really sorry that I did not put it clearly in my orginal message. I mean I want to pass "1 2" with 4 whitespace in between 1 and 2 but within the test.exe, there is only one whitespace left. However, the number of whitespaces is essential to me. Please let know if u know how to solve the problem. Thanks a lot.

[Maulin Vasavada]

hi,
i guess if u use the option i suggested then it should work fine for you.
try it and let me know if it works for you.
i tried the following code,

import java.io.*;
public class process {
public static void main(String[] s) throws Exception {
Runtime r = Runtime.getRuntime();
Process p = r.exec(new String[]{"mybatchfile.bat","1   2","3"});
System.out.println("p.wait() called");
p.waitFor();
System.out.println("p.wait() returned");
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = "";
line = br.readLine();
System.out.println("Reading process output");
while ( line != null ) {
System.out.println(line);
line = br.readLine();
}
br.close();
}
}

here is mybatchfile.bat,

echo off
echo "First Argument:" %1
echo "Second Argument:" %2

here is the output,
------------------------
C:\maulin>java process
p.wait() called
p.wait() returned
Reading process output
C:\maulin>echo off
"First Argument:" "1 2"
"Second Argument:" 3
--------------------------
it preserved spaces for my batch file.
regards
maulin

[Xu Li]

Hi Maulin,
Many thanks for your demo code. It solves my problem.
Rgs,
lixu