パッケージ com.kazurayam.subprocessj

クラス Subprocess

java.lang.Object

com.kazurayam.subprocessj.Subprocess

public class Subprocess
extends Object

Subprocess object allows you to spawn new OS subprocess using java.lang.ProcessBuilder. Subprocess#run() waits for the subprocess to finish, returns a CompletedProcess object which contains the return code, STDOUT and STDIN of the executed command.

A simple example as a JUnit5 test case:

 import com.kazurayam.subprocessj.Subprocess;
 import com.kazurayam.subprocessj.Subprocess.CompletedProcess;
 import org.junit.jupiter.api.Test;

 class SubprocessTest {
     @Test
     void test_demo() throws Exception {

         Subprocess subprocess = new Subprocess();

         // change the current working directory for the process in which a command is executed
         subprocess.cwd(new File(System.getProperty("user.home")));

         // execute a command in a forked process
         CompletedProcess cp = subprocess.run(Arrays.asList("ls", "-la", "."));

         // use the return code of the executed command
         System.out.println(cp.returncode());

         // use the STDOUT of the executed command
         cp.stdout().forEach(System.out::println);

         // use the STDERR of the executed command
         cp.stderr().forEach(System.out::println);
     }
 }
 

The following features are supported:

1. returning the return code from the Subpprocess
2. capturing the STDOUT from the Subprocess
3. capturing the STDERR from the Subprocess
4. starting a subprocess with a modified working directory

The following features are still to be considered:

1. PIPE: Connecting INPUT from other process as STDIN for the Subprocess
2. Starting a Subprocess with a modified Environment variables
3. inheriting the I/O of the Current Process

ネストされたクラスの概要

ネストされたクラス

修飾子とタイプ	クラス	説明
static final class	Subprocess.CompletedProcess	A Data Transfer Object that contains the return code, STDOUT and STDERR out of the executed subprocess.
static final class	Subprocess.StreamGobbler

コンストラクタの概要

コンストラクタ

コンストラクタ	説明
Subprocess()

メソッドの概要

修飾子とタイプ	メソッド	説明
Subprocess	cwd(File currentWorkingDirectory)	Change the current working directory.
Map<String,String>	environment()
String	environment(String key)
Subprocess.CompletedProcess	run(List<String> command)	Run the command written as a List<String>.

クラスから継承されたメソッド java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

コンストラクタの詳細

Subprocess

public Subprocess()

メソッドの詳細

environment

public Map<String,String> environment()

environment

public String environment(String key)

cwd

public Subprocess cwd(File currentWorkingDirectory)

Change the current working directory. As default, will be set as the current working directory of the caller process "."

パラメータ:

currentWorkingDirectory - a File object, which is a directory

戻り値:

the Subprocess object. for functional call chaining.

run

public Subprocess.CompletedProcess run(List<String> command)
                                throws IOException,
InterruptedException

Run the command written as a List<String>. Wait for the command to complete, then return a Subprocess.CompletedProcess instance, in which you can read: - the return code of the subprocess - the captured STDOUT of the subprocess - the captured STDERR of the subproess Referred to a Baeldung's article "Java Executor Wait for the Threads"

パラメータ:

command - E.g Array.asList("ls", "-la", ".")

戻り値:

a Subprocess.CompletedProcess instance

例外:

IOException - when failed to create a Thread to consume STDOUT/STDERR from the subprocess

InterruptedException - when a Thread that consumes STDOUT/STDERR from the subprocess was interrupted