当java作为服务运行时从java启动进程

Question

I have a java process running as windows server using prcorun ( http://commons.apache.org/proper/commons-daemon/ ); unfortunatly I have to launch an external legacy command written in C/C++.

both

Process myProcess = Runtime.getRuntime().exec(command);

and

Process myProcess = new ProcessBuilder(command, arg).start();

work well when java is launched as a stand-alone application, but when I start java as service it replies

command not found

also with

Process myProcess = Runtime.getRuntime().exec("dir");

command not found

I think is a problem due to windows services.

Any suggestion?

Answer 1

I would try to do a quick test and print the PATH environment variable in your service. What I usually found when you run some command as a service, the PATH might not be totally available (which can also explain why DIR is not working for you). If that the case, when starting the service, you have to make sure the PATH include both the normal bin and your legacy bin.

Answer 2

As the error says, the command is not found in the path. You'll need to set the environment variable PATH to the child process's environment. Look at exec(cmd, String[] env) method. You can create an array of environment variables (key value pairs) and pass it to exec().

Answer 3

In my case I used

cmd /c <<YOUR COMMAND>>

eg. Process myProcess = Runtime.getRuntime().exec("cmd /c dir");

also I added the envinronments. as suggested by smurf

private static String[] getEnv() {
    Map<String, String> env = System.getenv();
    String[] envp = new String[env.size()];
    int i = 0;
    for (Map.Entry<String, String> e : env.entrySet()) {
        envp[i++] = e.getKey() + "=" + e.getValue();
    }
    return envp;
}

...

Process myProcess = Runtime.getRuntime().exec("cmd /c dir",getEnv());

Alternative to java.lang.Runtime.exec() that can execute command lines as a single string?