cmd命令未在Java程序中运行

Question

I am trying to run a cmd command. Everything works fine but no output. I don't understand why. UPDATED CODE

import java.io.*;
import java.util.*;

class CmdTest {
    public static void main(String[] args) throws Exception {
        String command=   "ffmpeg -i D:\\test%d.jpg -vcodec mpeg4 outfile.avi";
        Process process;
        System.out.println("first stmt");
        try
        {
             process = Runtime.getRuntime().exec(command);
             Scanner kb = new Scanner(process.getInputStream());
             System.out.println("try block");
        } catch (IOException e)
        {
            e.printStackTrace();
        }
        System.out.println("last stmt");
    }
}

I am expecting execution of cmd command mentioned above. Nothing is going wrong during compilation and execution. However, command not executing write.

Answer 1

First, your code should give error because the line Scanner kb = new Scanner(process.getInputStream()); will not see process. process is defined inside try-catch .

Secondly, have you tried ffmpeg -i D:\\\\test%d.jpg -vcodec mpeg4 outfile.avi on command window ? If not, try it.

Third, instead of running that command try running some easy commands like dir , pwd etc.

Fourth, put some System.out.println("say something") inside the code, then you would be able to see where it fails/stops.