如何在Java中监视外部文件

Question

I have a .exe file, It takes .txt file as a Input and it returns .txt files as outputs.

I have 2 folders names are InputFiles and ExeFolder .

InputFiles folder have so many number of input files, which files are passing as a argument to .Exe file.

ExeFolder have .exe file, output files and only one Input file(we will get this file from InputFiles folder).

I want to build 1 web Application, It will work in the following way.

step 1 :

it checks, How many no of files are available in sourceDirectory as far my requirements.generally every time I want to find .txt files but for my code maintenance I passed filetype as a argument to function.

For this,I wrote the following code,it's working fine

 public List<File> ListOfFileNames(String directoryPath,String fileType)
{
    //Creating Object for File class
    File fileObject=new File(directoryPath);
    //Fetching all the FileNames under given Path
    File[] listOfFiles=fileObject.listFiles();
    //Creating another Array for saving fileNames, which are satisfying as far our requirements
    List<File> fileNames = new ArrayList<File>();
    for (int fileIndex = 0; fileIndex < listOfFiles.length; fileIndex++) 
    {
        if (listOfFiles[fileIndex].isFile())
        {
          //True condition,Array Index value is File
          if (listOfFiles[fileIndex].getName().endsWith(fileType)) 
          {
              //System.out.println(listOfFiles[fileIndex].getName());
              fileNames .add(listOfFiles[fileIndex]);
          }
        }  
    }
    return fileNames;
}

step 2:

I used for loop Based on length of ListOfFileNames[dir,filetype] ,For every Iteration file will be overwrite in ExeFolder folder. For this I wrote the following function.It's working fine

  public void FileMoving(File sourceFilePath,String destinationPath,String fileName)throws IOException 
 {
File destinationPathObject=new File(destinationPath);
if (
        (destinationPathObject.isDirectory())&&
        (sourceFilePath.isFile())
    )
    //both source and destination paths are available 
    {
        //creating object for File class
        File statusFileNameObject=new File(destinationPath+"/"+fileName);
        if (statusFileNameObject.isFile())
            //Already file is exists in Destination path
            {
                //deleted File
                statusFileNameObject.delete();
                //paste file from source to Destination path with fileName as value of fileName argument
                FileUtils.copyFile(sourceFilePath, statusFileNameObject);
            }
            //File is not exists in Destination path.
            {
                //paste file from source to Destination path with fileName as value of fileName argument
                FileUtils.copyFile(sourceFilePath, statusFileNameObject);
            }
    }
}

Step 3 :

.exe file will be run.For this I wrote the following function.Working fine but in this function I need to add some code for waiting.

   public void ExeternalFileProcessing(String DirectoryPath,String exeFilePath,String inputFileName) throws IOException
  {
//Creating Absolute file path of the executableFile
String executableFileName = DirectoryPath+"/"+exeFilePath;
//Assinging the InputFileName argument value to inputFile Variable
String inputFile=inputFileName;
//creating ProcessBuilderObject with 2 arguments
ProcessBuilder processBuilderObject=new ProcessBuilder(executableFileName,inputFile);
//creating object
File absoluteDirectory = new File(DirectoryPath);
//Assinging 
processBuilderObject.directory(absoluteDirectory);
//starting process
processBuilderObject.start();
//
//processBuilderObject.wait();
 }

Step 4:

once .exe process was done, then only next Iteration will be start. That means we need to monitor .exe process,whether is it done or not.

for integration, I wrote the following function name as Integration .

  public void Integration(String fileType,String sourcePath,String directoryPath,String executableName,String inputFileName)throws IOException
  {
    //created object for Class
    ExternalFileExecutions ExternalFileExecutionsObject=new ExternalFileExecutions();
    //calling Method from class object
    List<File> finalListNames=ExternalFileExecutionsObject.ListOfFileNames(sourcePath,fileType);
    for (int fileIndex = 0; fileIndex < finalListNames.size(); fileIndex++) 
    {
        //Copy and pasting file from SourcePath to destination Path
        ExternalFileExecutionsObject.FileMoving(
                                                    finalListNames.get(fileIndex),
                                                    directoryPath,
                                                    inputFileName
                                                );
        //Form here,.exe process will be start
        ExternalFileExecutionsObject.ExeternalFileProcessing(directoryPath,executableName,inputFileName);
    }
 }

I called these, Integration function in my main() in the following way.

public static void main(String[] args) throws IOException
{
//created object for Class
ExternalFileExecutions ExternalFileExecutionsObject=new ExternalFileExecutions();
ExternalFileExecutionsObject.Integration(
                                            ".txt",
                                            "C:/Users/Infratab Bangalore/Desktop/copy",
                                            "C:/Users/Infratab Bangalore/Desktop/Rods",
                                            "ThMapInfratab1-2.exe",
                                            "TMapInput.txt"
                                        );
 }

If you observer, my code,every thing was done except .exe monitoring,whether is it completed or not.Once first iteration process was done then it allows next Iteration.In second Iteration again .exe will be process.it just like queue .

Actually I never work on Java ,but using stackoverflow I wrote the above functions. Now I want to fix .exe monitoring.

I didn't found anything.

can anyone help me.

I hope, you guys understand what I am facing.

Thanks

Answer 1

For running an external process (a .exe program in this case), forget about Runtime.exec() . Instead use ProcessBuilder ; the documentation states that it's the preferred way to start up a sub-process these days.

Answer 2

Follow this quick tutorial over running .exe from java. It should be sufficient (4pages)

http://www.javaworld.com/jw-12-2000/jw-1229-traps.html?page=1

example

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

public class GoodWindowsExec
{
    public static void main(String args[])
    {


        try
        {            


            Runtime rt = Runtime.getRuntime();

            Process proc = rt.exec("cmd.exe /C ping"); // executing ping through commandshell of windows

            proc.getErrorStream() // errorstream

            proc.getInputStream()  // outputstream


            int exitVal = proc.waitFor(); // wait till process ends    
        } catch (Throwable t)
          {
            t.printStackTrace();
          }
    }
}