change directory and run the batch file in the same command prompt

Question

Hi, Is there any way to open the command prompt and change directory in the command prompt and run the batch file in the same command prompt using java.

I know how to open the command prompt using java. Thanks,

Answer 1

You can encode the CD and the batch file in the value for cmd.exe /K. From the doco (cmd /?):

Note that multiple commands separated by the command separator '&&' are accepted for string if surrounded by quotes.

For Example:

cmd /C "CD C:\ && Dir"
cmd /C "CD C:\Windows && Dir"
cmd /C "CD C:\Windows && MySuperSuperBatchFile"

For more detail, run:

cmd /?

from the command line.

Answer 2

It's difficult to do from Java for goofy platform-independence reasons: basically what if you're running java on a system that doesn't have hierarchical directories?

There are a number of workarounds depending on what you're really trying to do, but possibly the simplest is to run the eventual command using java.lang.Runtime.exec().

.

Answer 3

Keep the batch file in "path". You can execute it without going to any specific directory.

(For example you can have an entry "set path=%path%;C:..........\YourBatchFile.bat" in Autoexec.bat in Windows environment)

Answer 4

get the environment var "comspec" then exec %comspec% /c start/d directory /b batchfile.bat

Answer 5

A couple of the java.lang.Runtime.exec() variations does have a dir argument, so I assume you are not thinking of that?

You can compile the following C program and execute as a wrapper to start any program in any directory you want. If you use a String array with Runtime.exec you will avoid all issues of command line parsing/portability/proper quoting of the arguments.

I do not have any windows machine to test on here, but if you compile the C program to cdexe.exe you should be able to use it as the following:

public class Main {
        public static void main(String args[]) {
                String[] s = { "c:\\some\\place\\cdexe.exe",
                "c:\\start\\dir", "c:\\my\\batch\\file.bat", "arg1", "..." };
                try {
                        java.lang.Runtime.getRuntime().exec(s);
                } catch (java.io.IOException e) {
                        e.printStackTrace();
                }
        }
}

I guess unistd.h is maybe not available on windows, but just substitute with one containing a execv prototype.

#include <stdio.h>
#include <unistd.h>  // or hard code "int execv(const char *path, char *const argv[]);"

int main(int argc, char *argv[])
{
        if (argc < 3) {
                fprintf(stderr, "Error: Usage: %s <directory> <program> [arguments]\n", argv[0]);
                return 1;
        }
        if (chdir(argv[1]) < 0) {
                perror("Error");
                fprintf(stderr, "chdir(%s) failed\n", argv[1]);
                return 1;
        }
        argv[1] = argv[2];
        execv(argv[1], &argv[2]);      // use execvp if you want PATH to be searched
        perror("Error");
        fprintf(stderr, "execv returned\n");
        return 0;
}

Answer 6

Be wary of Java's exec. It can hang if the batch process fills the output buffer, and cause other weird problems.

I suggest you look at apache exec. Specifically for your needs you should note that the Executor interface has a setWorkingDirectory method.

Basic usage:

Executor exec = new DefaultExecutor();
exec.setWorkingDirectory("C:\\My\\Dir\\")
CommandLine cl = new CommandLine("mybatch.bat");
int exitvalue = exec.execute(cl);