如何在java中运行shell脚本.sh文件

Question

Objective

I wrote a simple java program where I want to rename a file and then simply I want to run my permission.sh file.

Problem Statement

What is happening that my file name is getting change successfully but permission.sh file is not being executed. Stuck need help!

Following is my code.

package nl.ggmd.file.Permission;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;

import org.apache.synapse.MessageContext;
import org.apache.synapse.mediators.AbstractMediator;

public class FilePermission extends AbstractMediator
{

  public boolean mediate(MessageContext context) { 
      try {
      File oldfile =new File("/ggmd/files/uploads/FIle contract1.csv");
        File newfile =new File("/ggmd/files/uploads/contract1.csv");

        if(oldfile.renameTo(newfile)){
            System.out.println("Rename succesful");
        }else{
            System.out.println("Rename failed");
        }


          Process proc = Runtime.getRuntime().exec("/opt/file/contracts/tst/permissions.sh"); 
          BufferedReader read = new BufferedReader(new InputStreamReader(
                  proc.getInputStream()));
          try {
              proc.waitFor();
          } catch (InterruptedException e) {
              System.out.println(e.getMessage());
          }
          while (read.ready()) {
              System.out.println(read.readLine());
          }
      } catch (IOException e) {
          System.out.println(e.getMessage());
      }


    return true;
  }
}

EDIT

This java code is s custom class mediator of WSO2 ESB and wso2 does not show logs of java mediator is its not possible for me to debug the issue.

Following is my permission.sh code.

#!/bin/bash
cd /ggmd/files/uploads/
file=contract1.csv

if [ ! -a $file ]
then
  sudo chmod 664 $file && echo "The file is now writable"
else
  echo "The file is already writable"
fi

Answer 1

it is much advisable to use the Process Builder . It is really built for this kind of tasks.

Your program permisions.sh is not an executable as Java understands it, even though the operating system understands it as an executable file.

You need to inform Java that the bash shell (or some other shell) is needed to execute your command. eg. /bin/bash is the path to the program that can run or execute your script. With that said you follow this code snippet bellow to fix get that working.

public class FilePermission extends AbstractMediator
{

  public boolean mediate(MessageContext context) { 
      try {
      File oldfile =new File("/ggmd/files/uploads/FIle contract1.csv");
        File newfile =new File("/ggmd/files/uploads/contract1.csv");

        if(oldfile.renameTo(newfile)){
            System.out.println("Rename succesful");
        }else{
            System.out.println("Rename failed");
        }

private final String commandPath = "/bin/bash";

private final String scriptPath = "/opt/file/contracts/tst/permissions.sh";


try {
        Process execCommand = new ProcessBuilder(commandPath, scriptPath).start();
        execCommand.waitFor();
    } catch (IOException e) {
        // handle exceptions
        System.out.println(e.getMessage());
    } catch (InterruptedException e) {
        System.out.println(e.getMessage());
    }


    return true;
  }
}

Please note that the above code may need some modification especially if your script(permissions.sh) may depend on the current working directory. with the above the working directory of the java code is being used.

but can be changed by calling the directory(File directory) method on the process object. then pass the new working directory path to it. In this case

Process execCommand = new ProcessBuilder(commandPath, scriptPath).directory(new File("/some/directory/to/be/used/")).start();

You can also call the execCommand.getErrorStream(); or execCommand.getInputStream(); where needed.