CODEWITHSUNDEEP
javabatch-file
English Learner
English Learner

Reputation: 51

bat file does not execute within Java

I have written some code for executing .bat file. which contains some commands like setting java classpath,etc..And finally there is one command which runs a Java class file.The HelloWorld class converts some xml file and generating a new xml file in some folder. When I double click .bat file, it executes fine, but when I try to run I am not getting any output as I was getting through double click the .bat file. How to make a batch execute and probably it would be nice if I could see the results through Java console.

Following is MyJava code to execute the .bat file

public void run2() {
        try {
            String []commands = {"cmd.exe","/C","C:/MyWork/Java/classes/run.bat"} ;
            Process p = Runtime.getRuntime().exec(commands);
            BufferedReader in = new BufferedReader(new InputStreamReader(
                    p.getInputStream()));
            String line = null;
            while ((line = in.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

And below the some commands which has been set to .bat file

set CLASSPATH=%CLASSPATH%;C:/MyWork/Java
set CLASSPATH=%CLASSPATH%;C:/MyWork/Java/classes
java -cp test.jar;test2.jar test.HelloWorld

Tried with "/C" commad as well. It does not execute. Actually it does not give effect of double click the .bat file. Is there any other way that I can try with?

I can see the contents inside the .bat file through Eclipse console. But it does not give the desired output. Desired output means when I double click .bat file, it executes well. But through java call, I can see the contents only .

Upvotes: 3

Views: 4507

Answers (4)

Ingo
Ingo

Reputation: 36339

You do not read the error output of your batch file, therefore, you'll never see any error messages printed from there or from CMD.EXE itself. In addition, the sub-program may stall and just wait for you to read the error stream.

Please see related discussions here: How to make a java program to print both out.println() and err.println() statements?

Upvotes: 0

Thomas W
Thomas W

Reputation: 14154

Windows uses \ backslash for Windows and MS-DOS path delimiter. Forward slash / is accepted by Java in the java.io package and translated to be a path delimiter, but will not be directly acceptable to Windows or accepted by the cmd.exe shell.

You may also need to specify either the working directory for the batch file to be executed in, or possibly a full path to the cmd.exe command interpreter.

See: Runtime.exec (String[] cmdarray, String[] envp, File dir)

String[] commands = {"C:\\Windows\\System32\\cmd.exe", "/c", 
    "C:\\MyWork\\Java\\classes\\run.bat"};
File workDir = new File( "C:/MyWork");
Process process = Runtime.getRuntime().exec( commands, null, workDir);

To verify if the batch file is run at all, add a pause command to the batch file. That will keep the window open so you can verify if the batch file is launched at all, and debug this stage-by-stage.

Upvotes: 0

Simiil
Simiil

Reputation: 2311

according to this, the Windows CMD needs the /c argument, to execute commands like this. try this:

String []commands = {"cmd.exe","/c","C:/MyWork/Java/classes/run.bat"} ;

Upvotes: 1

piet.t
piet.t

Reputation: 11921

When using cmd.exe use /C-Parameter to pass command:

String []commands = {"cmd.exe","/C","C:/MyWork/Java/classes/run.bat"} ;

Upvotes: 2

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