Process output from apache-commons exec

Question

I am at my wits end here. I\'m sure this is something simple and I most likely have huge holes in my understanding of java and streams. I think there are so many classes tha

Answer 1

Based on James A Wilson's answer I created the helper class "Execute". It wraps his answer into a solution that also supplies the exitValue for convenience.

A single line is necessary to execute a command this way:

ExecResult result=Execute.execCmd(cmd,expectedExitCode);

The following Junit Testcase tests and shows how to use it:

Junit4 test case:

package com.bitplan.newsletter;

import static org.junit.Assert.*;

import java.util.List;

import org.junit.Test;

import com.bitplan.cmd.Execute;
import com.bitplan.cmd.Execute.ExecResult;

/**
 * test case for the execute class
 * @author wf
 *
 */
public class TestExecute {
     @Test
   public void testExecute() throws Exception {
     String cmd="/bin/ls";
     ExecResult result = Execute.execCmd(cmd,0);
     assertEquals(0,result.getExitCode());
     List lines = result.getLines();
     assertTrue(lines.size()>0);
     for (String line:lines) {
         System.out.println(line);
     }
   }
}

Execute Java helper Class:

package com.bitplan.cmd;

import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;

import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.LogOutputStream;
import org.apache.commons.exec.PumpStreamHandler;

/**
 * Execute helper using apache commons exed
 *
 *  add this dependency to your pom.xml:
   
            org.apache.commons
            commons-exec
            1.2
        

 * @author wf
 *
 */
public class Execute {

    protected static java.util.logging.Logger LOGGER = java.util.logging.Logger
            .getLogger("com.bitplan.cmd");

    protected final static boolean debug=true;

    /**
     * LogOutputStream
     * http://stackoverflow.com/questions/7340452/process-output-from
     * -apache-commons-exec
     * 
     * @author wf
     * 
     */
    public static class ExecResult extends LogOutputStream {
        private int exitCode;
        /**
         * @return the exitCode
         */
        public int getExitCode() {
            return exitCode;
        }

        /**
         * @param exitCode the exitCode to set
         */
        public void setExitCode(int exitCode) {
            this.exitCode = exitCode;
        }

        private final List lines = new LinkedList();

        @Override
        protected void processLine(String line, int level) {
            lines.add(line);
        }

        public List getLines() {
            return lines;
        }
    }

    /**
     * execute the given command
     * @param cmd - the command 
     * @param exitValue - the expected exit Value
     * @return the output as lines and exit Code
     * @throws Exception
     */
    public static ExecResult execCmd(String cmd, int exitValue) throws Exception {
        if (debug)
            LOGGER.log(Level.INFO,"running "+cmd);
        CommandLine commandLine = CommandLine.parse(cmd);
        DefaultExecutor executor = new DefaultExecutor();
        executor.setExitValue(exitValue);
        ExecResult result =new ExecResult();
        executor.setStreamHandler(new PumpStreamHandler(result));
        result.setExitCode(executor.execute(commandLine));
        return result;
    }

}