通过 Netbeans 8.2（Java 项目）运行的 Octave 脚本没有创建文件（编辑：根本没有运行）

Question

I ran an Octave script through Java's ProcessBuilder and Process classes. I used Netbeans and the Script file is in resources folder of the Project I am doing.

When run from bash directly the script is working fine. When run from Java, I'm pretty sure the script is working fine.

In the below program,

#!/usr/bin/octave -qf
function ret = manipulateCell(x)

    x = x/max(x(:));
    x = x.*255;
    x = int32(x);
    a1 = mean(x(:));

    ret = a1<70;
end

img = imread('aaa.png');
imgInd = rgb2ind(img);
imgGray = ind2gray(imgInd,colormap());

sizeVector = 100*ones(1,20);


Cells =  mat2cell(imgGray,sizeVector,sizeVector);

ManipCells = cellfun(@manipulateCell,Cells);

file2D = fopen('data.txt','rw+');
dlmwrite(file2D,ManipCells);

Last two lines seem not to run from Netbeans; there is no output (ie, no output file is created).

Java Code which is used to run this script.

ProcessBuilder pb = new ProcessBuilder("src/resources/ProcessImg.m");
try{
    Process p = pb.start();
}
catch(IOException ex){
    ex.printStackTrace();
}

-- Edit:

I have just tried imshow(img) in between the above code. It didn't work either.

---

Edit:

How I verified that ProcessBuilder and Process work fine? and How do I know which directory I am in.

String command = "pwd";
ProcessBuilder pb = new ProcessBuilder(command);
        //pb.directory(new File("./"));

        try{
        Process p = pb.start();

        //Debug Code
        pb.redirectErrorStream(true);
        BufferedReader bf = new BufferedReader(new InputStreamReader(p.getInputStream()));

        String s;

        while((s=bf.readLine())!=null){
            System.out.println(s);
        }

        p.getInputStream().close();
        p.getOutputStream().close();
        p.getErrorStream().close();
        }
        catch(IOException ex){
            ex.printStackTrace();
        }

If the command string is pwd , the output is

/home/user/NetBeansProjects/Project

If the command string is ls , the output is

build
build.xml
manifest.mf
nbproject
src
test

I want to say that commands are being executed.

Also, process builder is identifying shebang notation.

---

The problem is NetBeans is not allowing ProcessImg.m to create files in it's directory by an external process probably.

---

#!/usr/bin/octave -qf
function ret = manipulateCell(x)

    x = x/max(x(:));
    x = x.*255;
    x = int32(x);
    a1 = mean(x(:));

    ret = a1<70;
end

img = imread('~/Desktop/aaa.png');

imgInd = rgb2ind(img);
imgGray = ind2gray(imgInd,colormap());

sizeVector = 100*ones(1,20);


Cells =  mat2cell(imgGray,sizeVector,sizeVector);

ManipCells = cellfun(@manipulateCell,Cells);

file2D = fopen('~/Desktop/data.txt','rw+');
dlmwrite(file2D,ManipCells);

I have put absolute path (from home) as suggested and it didn't work. Not only in NetBeans did the file hasn't been created but also on desktop.

Answer 1

I'm pretty sure that "ProcessBuilder" doesn't understand the Shebang in your script (or you haven't set it executable) and you have to call it like

ProcessBuilder pb = new ProcessBuilder("/usr/bin/octave",
                                       "src/resources/ProcessImg.m");

But this looks like a common problem so I suggest searching for "ProcessBuilder execute bash script" (or perl script) which gives many hits.

Also try an absolute path to your script and explicitely close your file on exit.