从Java执行另一个应用程序

时间:2010-08-12 14:52:14

标签: java processbuilder

我需要执行一个执行另一个Java应用程序的批处理文件。 我不关心它是否成功执行,我不必捕获任何错误。

是否可以使用ProcessBuilder执行此操作?如果我不捕获错误会有什么后果?

但是,我的要求只是执行另一个Java应用程序。

10 个答案:

答案 0 :(得分:29)

Runtime.getRuntime().exec()方法非常麻烦,您很快就会发现。

看看Apache Commons Exec项目。它抽象了许多与使用Runtime.getRuntime().exec()ProcessBuilder API相关的常见问题。

这很简单:

String line = "myCommand.exe";
CommandLine commandLine = CommandLine.parse(line);
DefaultExecutor executor = new DefaultExecutor();
executor.setExitValue(1);
int exitValue = executor.execute(commandLine);

答案 1 :(得分:25)

是的,可以使用ProcessBuilder。

ProcessBuilder示例:

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

public class CmdProcessBuilder {
  public static void main(String args[]) 
     throws InterruptedException,IOException 
  {
    List<String> command = new ArrayList<String>();
    command.add(args[0]);


    ProcessBuilder builder = new ProcessBuilder(command);
    Map<String, String> environ = builder.environment();

    final Process process = builder.start();
    InputStream is = process.getInputStream();
    InputStreamReader isr = new InputStreamReader(is);
    BufferedReader br = new BufferedReader(isr);
    String line;
    while ((line = br.readLine()) != null) {
      System.out.println(line);
    }
    System.out.println("Program terminated!");
  }
}

检查以下示例:

http://www.rgagnon.com/javadetails/java-0014.html

http://www.java-tips.org/java-se-tips/java.util/from-runtime.exec-to-processbuilder.html

答案 2 :(得分:4)

我假设您知道如何使用ProcessBuilder执行命令。

从Java执行命令总是应该从进程中读取stdout和stderr流。否则可能会发生缓冲区已满并且因为写入stdout或stderr块而​​无法继续进程。

答案 3 :(得分:4)

您可以使用

执行批处理指令或任何其他应用程序
Runtime.getRuntime().exec(cmd);
  • cmd是命令或应用程序路径。

此外,您可以等待执行并获取返回代码(以检查其是否正确执行):

  Process p = Runtime.getRuntime().exec(cmd);
  p.waitFor();
  int exitVal = p.exitValue();

您可以在此处详细了解不同类型的通话 http://www.rgagnon.com/javadetails/java-0014.html

答案 4 :(得分:4)

以下是如何使用ProcessBuilder执行远程应用程序的示例。由于您不关心输入/输出和/或错误,因此您可以执行以下操作:

List<String> args = new ArrayList<String>();
args.add ("script.bat"); // command name
args.add ("-option"); // optional args added as separate list items
ProcessBuilder pb = new ProcessBuilder (args);
Process p = pb.start();
p.waitFor();

waitFor()方法将等到进程结束后再继续。此方法返回进程的错误代码,但由于您不关心它,我没有将它放在示例中。

答案 5 :(得分:2)

我知道这是一个较老的线程,但是我认为我可能有必要加入我的实现,因为我发现这个线程尝试做与OP相同的事情,除了Root级访问,但没有&#39;真的找到我正在寻找的解决方案。下面的方法创建一个静态根级别shell,用于执行命令而不考虑错误检查,甚至命令执行成功。

我使用它创建的Android手电筒应用程序,可以将LED设置为不同的亮度级别。通过删除所有错误检查和其他绒毛,我可以让LED在短至3毫秒内切换到指定的亮度级别,这打开了LightTones(带光的RingTones)的大门。有关应用程序本身的更多详细信息,请访问:http://forum.xda-developers.com/showthread.php?t=2659842

以下是整个课程。

public class Shell {
    private static Shell rootShell = null;
    private final Process proc;
    private final OutputStreamWriter writer;

    private Shell(String cmd) throws IOException {
        this.proc = new ProcessBuilder(cmd).redirectErrorStream(true).start();
        this.writer = new OutputStreamWriter(this.proc.getOutputStream(), "UTF-8");
    }

    public void cmd(String command)  {
        try {
            writer.write(command+'\n');
            writer.flush();
        } catch (IOException e) {   }
    }

    public void close() {
        try {
            if (writer != null) {  writer.close();
                if(proc != null) {  proc.destroy();    }
            }
        } catch (IOException ignore) {}
    }

    public static void exec(String command) {   Shell.get().cmd(command);   }

    public static Shell get() {
        if (Shell.rootShell == null) {
            while (Shell.rootShell == null) {
                try {   Shell.rootShell = new Shell("su"); //Open with Root Privileges 
                } catch (IOException e) {   }
            }
        } 
        return Shell.rootShell;
    }
}

然后在我的应用程序中的任何地方运行命令,例如更改LED亮度,我只需调用:

Shell.exec("echo " + bt.getLevel() + " > "+ flashfile);

答案 6 :(得分:2)

下面的代码片段编写用于使用ProcessBuilder编译和运行外部JAVA程序,我们可以运行任何外部程序。确保必须在OS环境中设置JAVA_HOME。见more

package com.itexpert.exam;

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

 public class JavaProcessBuilder {
/**
 *  Provide absolute JAVA file path 
 */
private static final String JAVA_FILE_LOCATION = "D:\\Test.java";

public static void main(String args[]) throws IOException{
    String command[] = {"javac",JAVA_FILE_LOCATION};
    ProcessBuilder processBuilder = new ProcessBuilder(command);

    Process process = processBuilder.start();
    /**
     * Check if any errors or compilation errors encounter then print on Console.
     */

    if( process.getErrorStream().read() != -1 ){
        print("Compilation Errors",process.getErrorStream());
    }
    /**
     * Check if javac process execute successfully or Not
     * 0 - successful
     */
    if( process.exitValue() == 0 ){
        process = new ProcessBuilder(new String[]{"java","-cp","d:\\","Test"}).start();
        /** Check if RuntimeException or Errors encounter during execution then print errors on console
         *  Otherwise print Output
        */
        if( process.getErrorStream().read() != -1 ){
            print("Errors ",process.getErrorStream());
        }
        else{
            print("Output ",process.getInputStream());
        }

    }
}

private static void print(String status,InputStream input) throws IOException{
    BufferedReader in = new BufferedReader(new InputStreamReader(input));
    System.out.println("************* "+status+"***********************");
    String line = null;
    while((line = in.readLine()) != null ){
        System.out.println(line);
    }
    in.close();
}

}

答案 7 :(得分:1)

如果您不关心返回值,可以使用Runtime.getRuntime().exec("path.to.your.batch.file");

答案 8 :(得分:1)

我可以看到有一个比apache commons exec库更好的库。 您可以使用Java Secure Shell(JSch)执行您的工作。

我遇到了同样的问题。我用JSch来解决这个问题。 Apache commons在另一台服务器上运行命令时遇到了一些问题。加上JSch给了我结果和错误InputStreams。我发现它更优雅。可以在此处找到示例解决方案:http://wiki.jsch.org/index.php?Manual%2FExamples%2FJschExecExample

    import java.io.InputStream;
    import java.io.BufferedReader;
    import java.io.InputStreamReader;

    import org.apache.commons.exec.*;

    import com.jcraft.*;
    import com.jcraft.jsch.JSch;
    import com.jcraft.jsch.Session;
    import com.jcraft.jsch.ChannelExec;

    import java.util.Arrays;
    import java.util.List;
    import java.util.ArrayList;
    import java.util.HashMap;


    public class  exec_linux_cmd {
        public HashMap<String,List<String>> exec_cmd (
                String USERNAME,
                String PASSWORD,
                String host,
                int port,
                String cmd)
        {
            List<String> result = new ArrayList<String>();
            List<String> errors = new ArrayList<String>();
            HashMap<String,List<String>> result_map = new HashMap<String,List<String>>();
        //String line = "echo `eval hostname`";
            try{
            JSch jsch = new JSch();
            /*
            * Open a new session, with your username, host and port
            * Set the password and call connect.
            * session.connect() opens a new connection to remote SSH server.
            * Once the connection is established, you can initiate a new channel.
            * this channel is needed to connect and remotely execute the program
            */

            Session session = jsch.getSession(USERNAME, host, port);
            session.setConfig("StrictHostKeyChecking", "no");
            session.setPassword(PASSWORD);
            session.connect();

            //create the excution channel over the session
            ChannelExec channelExec = (ChannelExec)session.openChannel("exec");

            // Gets an InputStream for this channel. All data arriving in as messages from the remote side can be read from this stream.
            InputStream in = channelExec.getInputStream();
            InputStream err = channelExec.getErrStream();

            // Set the command that you want to execute
            // In our case its the remote shell script

            channelExec.setCommand(cmd);

            //Execute the command
            channelExec.connect();

            // read the results stream
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            // read the errors stream. This will be null if no error occured
            BufferedReader err_reader = new BufferedReader(new InputStreamReader(err));
            String line;

            //Read each line from the buffered reader and add it to result list
            // You can also simple print the result here

            while ((line = reader.readLine()) != null)
            {
                result.add(line);
            }

            while ((line = err_reader.readLine()) != null)
            {
                errors.add(line);
            }

            //retrieve the exit status of the remote command corresponding to this channel
            int exitStatus = channelExec.getExitStatus();
            System.out.println(exitStatus);

            //Safely disconnect channel and disconnect session. If not done then it may cause resource leak
            channelExec.disconnect();
            session.disconnect();
            System.out.println(exitStatus);
            result_map.put("result", result);
            result_map.put("error", errors);

            if(exitStatus < 0){
                System.out.println("Done--> " + exitStatus);
                System.out.println(Arrays.asList(result_map));
                //return errors;
            }
            else if(exitStatus > 0){
                System.out.println("Done -->" + exitStatus);
                System.out.println(Arrays.asList(result_map));
                //return errors;
            }
            else{
               System.out.println("Done!");
               System.out.println(Arrays.asList(result_map));
               //return result;
            }

            }
            catch (Exception e)
            {
                System.out.print(e);
            }

            return result_map;
        }



        //CommandLine commandLine = CommandLine.parse(cmd);
        //DefaultExecutor executor = new DefaultExecutor();
        //executor.setExitValue(1);
        //int exitValue = executor.execute(commandLine);

           public static void main(String[] args)
           {
               //String line = args[0];
               final String USERNAME ="abc"; // username for remote host
               final String PASSWORD ="abc"; // password of the remote host
               final String host = "3.98.22.10"; // remote host address
               final int port=22; // remote host port
               HashMap<String,List<String>> result = new HashMap<String,List<String>>();

               //String cmd = "echo `eval hostname`"; // command to execute on remote host
               exec_linux_cmd ex = new exec_linux_cmd();

               result = ex.exec_cmd(USERNAME, PASSWORD , host, port, cmd);
               System.out.println("Result ---> " + result.get("result"));
               System.out.println("Error Msg ---> " +result.get("error"));
               //System.out.println(Arrays.asList(result));

               /*
               for (int i =0; i < result.get("result").size();i++)
               {
                        System.out.println(result.get("result").get(i));
               }
               */

           }
    }

编辑1:为了找到在Unix上执行的进程(如果它是一个长期运行的进程),请使用ps -aux | grep java。应该与您正在执行的unix命令一起列出进程ID。

答案 9 :(得分:0)

您只需使用Runtime.exec()

即可