Como executar comandos de terminal do Windows, Linux, macOS em Java e retornar o resultado completo

Publicados: 2019-02-26

Execute os comandos Linux mkdir, ls -ltra e ping em Java

Executar um system command é relativamente simples – uma vez que você o tenha visto pela primeira vez.

Envolve o uso de duas classes Java, a classe Runtime e a classe Process. Basicamente, você usa o exec method da classe Runtime para executar o comando como um processo separado.

Invocar o método exec retorna um objeto Process para gerenciar o subprocesso. Em seguida, você usa os métodos getInputStream() e getErrorStream() do objeto Process para ler a saída normal do comando e a saída de erro do comando. O que você faz com a saída do comando executado depende inteiramente de você e do aplicativo que está criando.

Os métodos ProcessBuilder.start() e Runtime.exec criam um processo nativo e retornam uma instância de uma subclasse de Process que pode ser usada para controlar o processo e obter informações sobre ele.

A classe Process fornece métodos para realizar a entrada do processo, executar a saída para o processo, aguardar a conclusão do processo, verificar o status de saída do processo e destruir (matar) o processo.

Os métodos que criam processos podem não funcionar bem para processos especiais em determinadas plataformas nativas, como processos nativos de janelas, processos daemon, processos Win16/DOS no Microsoft Windows ou scripts de shell.

Por padrão, o subprocesso criado não possui seu próprio terminal ou console. Todas as suas operações de E/S padrão (ou seja, stdin, stdout, stderr) serão redirecionadas para o processo pai, onde podem ser acessadas através dos fluxos obtidos usando os métodos getOutputStream() , getInputStream() e getErrorStream() .

O processo pai usa esses fluxos para alimentar a entrada e obter a saída do subprocesso. Como algumas plataformas nativas fornecem apenas um tamanho de buffer limitado para fluxos de entrada e saída padrão, a falha em gravar prontamente o fluxo de entrada ou ler o fluxo de saída do subprocesso pode causar o bloqueio do subprocesso ou até mesmo um impasse.

Abaixo estão dois exemplos Java simples para sua referência.

Exemplo 1. Execute mkdir, ls -ltra e ping em Java

  • Criar arquivo CrunchifyCommandJava.java
  • Execute mkdir /Users/ashah/Desktop/new-folder
  • Execute ls -ltra /Library
  • Execute ping crunchify.com

CrunchifyCommandJava.java
Java
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package crunchify . com . tutorials ;
 
import java . io . BufferedReader ;
import java . io . IOException ;
import java . io . InputStream ;
import java . io . InputStreamReader ;
 
/**
* @author Crunchify.com
* Execute Linux commands using Java. We are executing mkdir, ls -ltra and ping in this tutorial
*/
 
public class CrunchifyCommandJava {
public printOutput getStreamWrapper ( InputStream is , String type ) {
return new printOutput ( is , type ) ;
}
 
public static void main ( String [ ] args ) {
 
Runtime rt = Runtime . getRuntime ( ) ;
CrunchifyCommandJava rte = new CrunchifyCommandJava ( ) ;
printOutput errorReported , outputMessage ;
 
try {
Process proc = rt . exec ( "mkdir /Users/ashah/Desktop/new-folder" ) ;
errorReported = rte . getStreamWrapper ( proc . getErrorStream ( ) , "ERROR" ) ;
outputMessage = rte . getStreamWrapper ( proc . getInputStream ( ) , "OUTPUT" ) ;
errorReported . start ( ) ;
outputMessage . start ( ) ;
} catch ( IOException e ) {
e . printStackTrace ( ) ;
}
 
try {
Process proc = rt . exec ( "ls -ltra /Library" ) ;
errorReported = rte . getStreamWrapper ( proc . getErrorStream ( ) , "ERROR" ) ;
outputMessage = rte . getStreamWrapper ( proc . getInputStream ( ) , "OUTPUT" ) ;
errorReported . start ( ) ;
outputMessage . start ( ) ;
} catch ( IOException e ) {
e . printStackTrace ( ) ;
}
try {
Process proc = rt . exec ( "ping crunchify.com" ) ;
errorReported = rte . getStreamWrapper ( proc . getErrorStream ( ) , "ERROR" ) ;
outputMessage = rte . getStreamWrapper ( proc . getInputStream ( ) , "OUTPUT" ) ;
errorReported . start ( ) ;
outputMessage . start ( ) ;
} catch ( IOException e ) {
e . printStackTrace ( ) ;
}
 
}
 
private class printOutput extends Thread {
InputStream is = null ;
 
printOutput ( InputStream is , String type ) {
this . is = is ;
}
 
public void run ( ) {
String s = null ;
try {
BufferedReader br = new BufferedReader (
new InputStreamReader ( is ) ) ;
while ( ( s = br . readLine ( ) ) ! = null ) {
System . out . println ( s ) ;
}
} catch ( IOException ioe ) {
ioe . printStackTrace ( ) ;
}
}
}
}

Certifique-se de alterar o caminho de acordo no programa acima de acordo com as configurações do sistema.

Saída do console do Eclipse:

Basta executar o programa acima como um aplicativo Java e você verá um resultado semelhante.

result
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mkdir: /Users/ashah/Desktop/new-file-created.txt: File created
 
 
total 0
drwxr-xr-x    3 root  wheel    96 Aug 17  2018 Compositions
drwxr-xr-x@   2 root  wheel    64 Aug 17  2018 GPUBundles
drwxr-xr-x    2 root  wheel    64 Aug 17  2018 SystemProfiler
drwxr-xr-x    2 root  wheel    64 Aug 17  2018 ColorPickers
-rw-r--r--    1 root  wheel     0 Aug 17  2018 .localized
drwxr-xr-x    2 root  wheel    64 Aug 17  2018 StartupItems
drwxr-xr-x    3 root  wheel    96 Aug 17  2018 Speech
drwxr-xr-x    4 root  wheel   128 Aug 17  2018 Ruby
drwxr-xr-x@   2 root  wheel    64 Aug 17  2018 CoreAnalytics
drwxr-xr-x    3 root  wheel    96 Aug 17  2018 DirectoryServices
drwxr-xr-x    5 root  wheel   160 Aug 17  2018 WebServer
drwxr-xr-x    3 root  wheel    96 Aug 17  2018 Perl
drwxr-xr-x    2 root  wheel    64 Aug 17  2018 ScriptingAdditions
drwxr-xr-x    2 root  wheel    64 Aug 17  2018 Keyboard Layouts
drwxr-xr-x    3 root  wheel    96 Aug 17  2018 Graphics
drwxr-xr-x    3 root  wheel    96 Aug 17  2018 Python
drwxr-xr-x    8 root  wheel   256 Oct 11 16:51 User Pictures
drwxr-xr-x    3 root  wheel    96 Oct 11 16:51 Screen Savers
drwxr-xr-x   51 root  wheel  1632 Oct 11 16:51 Desktop Pictures
drwxr-xr-x    2 root  wheel    64 Oct 18 18:51 Contextual Menu Items
drwxr-xr-x    2 root  wheel    64 Oct 18 18:51 Components
drwxr-xr-x    5 root  wheel   160 Oct 21 16:03 OpenDirectory
drwxr-xr-x    2 root  wheel    64 Oct 23 20:43 Input Methods
drwxr-xr-x    4 root  wheel   128 Oct 29 23:49 Video
drwxr-xr-x    3 root  wheel    96 Nov  5 21:20 Messages
drwxr-xr-x@   3 root  wheel    96 Nov 12 22:37 MessageTracer
drwxr-xr-x    3 root  wheel    96 Nov 12 22:55 CoreMediaIO
drwxr-xr-x    3 root  wheel    96 Nov 29 23:38 Sandbox
drwxr-xr-x    3 root  wheel    96 Nov 29 23:38 Filesystems
drwxr-xr-x    8 root  wheel   256 Nov 29 23:40 Image Capture
drwxr-xr-x    4 root  wheel   128 Nov 29 23:41 Java
drwxr-xr-x    4 root  wheel   128 Nov 29 23:41 QuickTime
drwxr-xr-x   10 root  wheel   320 Nov 29 23:45 Scripts
drwxrwxr-t  182 root  admin  5824 Nov 29 23:47 Fonts
drwxr-xr-x    4 root  wheel   128 Nov 29 23:49 QuickLook
drwxr-xr-x    4 root  wheel   128 Nov 29 23:49 Spotlight
drwxr-xr-x   37 root  wheel  1184 Nov 29 23:50 Modem Scripts
drwxr-xr-x    4 root  wheel   128 Feb 11 13:00 ColorSync
drwxr-xr-x    4 root  wheel   128 Feb 11 13:04 Security
drwxr-xr-x    8 root  wheel   256 Feb 11 13:04 PDF Services
drwxr-xr-x    3 root  wheel    96 Feb 11 13:05 Catacomb
drwxr-xr-x    9 root  wheel   288 Feb 11 13:05 Frameworks
drwxr-xr-x    3 root  wheel    96 Feb 11 13:05 Automator
drwxr-xr-x   10 root  wheel   320 Feb 11 13:05 Audio
drwxr-xr-x    3 root  wheel    96 Feb 11 13:05 Tanium
drwxr-xr-x+  68 root  wheel  2176 Feb 11 13:05 .
drwxr-xr-x    3 root  admin    96 Feb 11 13:05 Developer
drwxr-xr-x    8 root  wheel   256 Feb 11 13:05 Documentation
drwxr-xr-x    4 root  wheel   128 Feb 11 13:05 DropboxHelperTools
drwxrwxr-x   14 root  admin   448 Feb 11 13:07 Receipts
drwxr-xr-x    4 root  wheel   128 Feb 11 13:07 SystemMigration
drwxr-xr-x@   4 root  wheel   128 Feb 11 13:10 StagedExtensions
drwxr-xr-x   14 root  wheel   448 Feb 11 18:26 Widgets
drwxr-xr-x   13 root  wheel   416 Feb 11 18:26 Extensions
drwxr-xr-x   29 root  wheel   928 Feb 11 18:35 ..
drwxr-xr-x    9 root  wheel   288 Feb 17 12:38 Logs
drwxrwxrwt   11 root  admin   352 Feb 22 13:29 Caches
drwxr-xr-x   11 root  wheel   352 Feb 22 13:36 LaunchAgents
drwxr-xr-x    2 root  wheel    64 Feb 22 13:36 PreferencePanes
drwxr-xr-x    9 root  wheel   288 Feb 22 13:36 Internet Plug-Ins
drwxr-xr-t    7 root  wheel   224 Feb 22 13:36 PrivilegedHelperTools
drwxr-xr-x   18 root  wheel   576 Feb 22 13:36 LaunchDaemons
drwxr-xr-x   25 root  admin   800 Feb 22 16:03 Application Support
dr-xr-xr-x    9 root  wheel   288 Feb 25 10:24 Printers
drwxr-xr-x@   5 root  wheel   160 Feb 25 10:24 Updates
drwxr-xr-x   10 root  wheel   320 Feb 25 14:12 Keychains
drwxr-xr-x   25 root  wheel   800 Feb 26 08:07 Managed Preferences
drwxr-xr-x   67 root  wheel  2144 Feb 26 08:07 Preferences
 
 
PING crunchify.com (35.197.114.216): 56 data bytes
64 bytes from 35.197.114.216: icmp_seq=0 ttl=54 time=70.275 ms
64 bytes from 35.197.114.216: icmp_seq=1 ttl=54 time=73.876 ms
64 bytes from 35.197.114.216: icmp_seq=2 ttl=54 time=68.134 ms
64 bytes from 35.197.114.216: icmp_seq=3 ttl=54 time=75.951 ms
64 bytes from 35.197.114.216: icmp_seq=4 ttl=54 time=70.205 ms

Exemplo-2.

  • CrunchifyRunCommand.java
  • Execute o comando ps -few para obter uma lista de todos os processos em execução no seu sistema.

CrunchifyRunCommand.java
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package crunchify . com . tutorials ;
 
import java . io . BufferedReader ;
import java . io . IOException ;
import java . io . InputStreamReader ;
 
/**
* @author Crunchify.com
* Execute ps -few command in Java to get list of all processes
*/
 
public class CrunchifyRunCommand {
 
public static void main ( String [ ] args ) {
String s = null ;
 
try {
 
// Process provides control of native processes started by ProcessBuilder.start and Runtime.exec.
// getRuntime() returns the runtime object associated with the current Java application.
Process p = Runtime . getRuntime ( ) . exec ( "ps -few" ) ;
 
BufferedReader stdInput = new BufferedReader ( new InputStreamReader ( p . getInputStream ( ) ) ) ;
BufferedReader stdError = new BufferedReader ( new InputStreamReader ( p . getErrorStream ( ) ) ) ;
 
// read the output from the command
System . out . println ( "Here is the standard output of the command:\n" ) ;
while ( ( s = stdInput . readLine ( ) ) ! = null ) {
System . out . println ( s ) ;
}
 
// read any errors from the attempted command
System . out . println ( "Here is the standard error of the command (if any):\n" ) ;
while ( ( s = stdError . readLine ( ) ) ! = null ) {
System . out . println ( s ) ;
}
 
System . exit ( 0 ) ;
} catch ( IOException e ) {
System . out . println ( "exception happened - here's what I know: " ) ;
e . printStackTrace ( ) ;
System . exit ( - 1 ) ;
}
}
}

Saída do console do Eclipse:

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Here is the standard output of the command :
 
   UID   PID   PPID    C STIME   TTY           TIME CMD
     0      1      0    0 Fri09PM ? ?          7 : 14.76 / sbin / launchd
     0      44      1    0 Fri09PM ? ?          0 : 09.67 / usr / sbin / syslogd
     0      45      1    0 Fri09PM ? ?          0 : 12.95 / usr / libexec / UserEventAgent ( System )
     0      49      1    0 Fri09PM ? ?          0 : 04.41 / System / Library / PrivateFrameworks / Uninstall . framework / Resources / uninstalld
     0      50      1    0 Fri09PM ? ?          0 : 26.75 / usr / libexec / kextd
     0      51      1    0 Fri09PM ? ?          2 : 00.76 / System / Library / Frameworks / CoreServices . framework / Versions / A / Frameworks / FSEvents . framework / Versions / A / Support / fseventsd
     0      53      1    0 Fri09PM ? ?          4 : 16.25 / usr / local / jamf / bin / jamf launchDaemon - enforceRestrictions - monitorNetworkStateChanges
     0      54      1    0 Fri09PM ? ?          0 : 01.29 / System / Library / PrivateFrameworks / MediaRemote . framework / Support / mediaremoted
   55      57      1    0 Fri09PM ? ?          0 : 01.23 / System / Library / CoreServices / appleeventsd -- server
     0      58      1    0 Fri09PM ? ?          4 : 21.14 / usr / sbin / systemstats -- daemon
     0      60      1    0 Fri09PM ? ?          0 : 41.10 / usr / libexec / configd
     0      61      1    0 Fri09PM ? ?          1 : 03.98 / System / Library / CoreServices / powerd . bundle / powerd
     0      62      1    0 Fri09PM ? ?          0 : 00.89 / Library / Application Support / JAMF / Jamf . app / Contents / MacOS / JamfDaemon . app / Contents / MacOS / JamfDaemon
     0      65      1    0 Fri09PM ? ?          0 : 43.84 / usr / libexec / logd
     0      66      1    0 Fri09PM ? ?          0 : 00.02 / usr / libexec / keybagd - t 15
     0      73      1    0 Fri09PM ? ?          3 : 26.45 / System / Library / Frameworks / CoreServices . framework / Frameworks / Metadata . framework / Support / mds
   240      74      1    0 Fri09PM ? ?          0 : 00.11 / System / Library / CoreServices / iconservicesd
     0      75      1    0 Fri09PM ? ?          0 : 03.39 / usr / libexec / diskarbitrationd
     0      79      1    0 Fri09PM ? ?          0 : 00.73 / System / Library / CoreServices / backupd . bundle / Contents / Resources / backupd - helper - launchd
     0      80      1    0 Fri09PM ? ?          0 : 03.84 / usr / libexec / coreduetd
     0      84      1    0 Fri09PM ? ?          2 : 30.59 / usr / libexec / opendirectoryd
     0      85      1    0 Fri09PM ? ?          0 : 17.45 / System / Library / PrivateFrameworks / ApplePushService . framework / apsd
     0      86      1    0 Fri09PM ? ?          0 : 00.67 / System / Library / PrivateFrameworks / Noticeboard . framework / Versions / A / Resources / nbstated
     0      87      1    0 Fri09PM ? ?          0 : 16.91 / System / Library / CoreServices / launchservicesd
   266      88      1    0 Fri09PM ? ?          0 : 06.48 / usr / libexec / timed
     0      89      1    0 Fri09PM ? ?          0 : 25.37 / usr / sbin / securityd - i
   213      90      1    0 Fri09PM ? ?          0 : 01.16 / System / Library / PrivateFrameworks / MobileDevice . framework / Versions / A / Resources / usbmuxd - launchd
   205      92      1    0 Fri09PM ? ?          0 : 59.64 / usr / libexec / locationd
     0      94      1    0 Fri09PM ? ?          0 : 00.08 autofsd
   244      95      1    0 Fri09PM ? ?          0 : 03.06 / usr / libexec / displaypolicyd - k 1
     0      98      1    0 Fri09PM ? ?          0 : 11.56 / usr / libexec / dasd
     0      99      1    0 Fri09PM ? ?          0 : 00.71 / System / Library / PrivateFrameworks / Heimdal . framework / Helpers / kdc
     0    103      1    0 Fri09PM ? ?          0 : 00.87 / Library / Tanium / TaniumClient / TaniumClient - d
110048994    104      1    0 Fri09PM ? ?          0 : 34.02 / System / Library / CoreServices / loginwindow . app / Contents / MacOS / loginwindow console
     0    105      1    0 Fri09PM ? ?          0 : 00.76 / System / Library / CoreServices / logind
     0    106      1    0 Fri09PM ? ?          0 : 00.66 / System / Library / PrivateFrameworks / GenerationalStorage . framework / Versions / A / Support / revisiond
     0    107      1    0 Fri09PM ? ?          0 : 00.03 / usr / sbin / KernelEventAgent
     0    109      1    0 Fri09PM ? ?          1 : 58.55 / usr / sbin / bluetoothd
   261    110      1    0 Fri09PM ? ?          13 : 48.55 / usr / libexec / hidd
     0    112      1    0 Fri09PM ? ?          0 : 06.37 / usr / libexec / corebrightnessd -- launchd
     0    113      1    0 Fri09PM ? ?          0 : 04.23 / usr / libexec / AirPlayXPCHelper
     0    114      1    0 Fri09PM ? ?          1 : 07.01 / usr / sbin / notifyd
   241    116      1    0 Fri09PM ? ?          0 : 11.70 / usr / sbin / distnoted daemon
     0    119      1    0 Fri09PM ? ?          0 : 03.99 / usr / libexec / amfid
     0    123      1    0 Fri09PM ? ?          0 : 09.47 / usr / libexec / syspolicyd
     0    124      1    0 Fri09PM ? ?          0 : 05.81 / System / Library / Frameworks / Security . framework / Versions / A / XPCServices / authd . xpc / Contents / MacOS / authd
     0    142      1    0 Fri09PM ? ?          1 : 31.63 / usr / sbin / cfprefsd daemon
     0    143      1    0 Fri09PM ? ?          0 : 23.54 / System / Library / CoreServices / coreservicesd
     0    166      1    0 Fri09PM ? ?          0 : 21.34 / System / Library / PrivateFrameworks / CoreDuetContext . framework / Resources / contextstored

Estes são alguns dos processos em execução no meu MacBook Pro. Existem alguns mais, mas colados muito poucos.

Espero que este tutorial ajude você a executar qualquer comando de terminal linux e macOS usando um programa Java simples. Deixe-me saber para quaisquer perguntas.