これは、外部プロセスを起動するために使用するライブラリ コードの「大まかな」例です。
基本的に、これは 3 つのスレッドを使用します。1 つ目は、実際にコマンドを実行し、それが存在するまで待機するために使用されます。
他の 2 つは、プロセスの出力ストリームと入力ストリームを処理します。これにより、これらが互いに独立し、一方が他方をブロックできなくなります。
次に、何かが発生したときに通知されるリスナーと全体が結び付けられます。
エラー処理は改善される可能性があります (実際に何が/誰が失敗したかについて失敗条件が少し不明確であるため)、基本的な概念はそこにあります...
これは、気にせずにプロセスを起動できることを意味します...（必要になるまで）
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
public class TestBackgroundProcess {
public static void main(String[] args) {
new TestBackgroundProcess();
}
public TestBackgroundProcess() {
BackgroundProcess bp = new BackgroundProcess("java", "-jar", "dist/BackgroundProcess.jar");
bp.setListener(new ProcessListener() {
@Override
public void charRead(BackgroundProcess process, char value) {
}
@Override
public void lineRead(BackgroundProcess process, String text) {
System.out.println(text);
}
@Override
public void processFailed(BackgroundProcess process, Exception exp) {
System.out.println("Failed...");
exp.printStackTrace();
}
@Override
public void processCompleted(BackgroundProcess process) {
System.out.println("Completed - " + process.getExitValue());
}
});
System.out.println("Execute command...");
bp.start();
bp.send("dir");
bp.send("exit");
System.out.println("I'm not waiting here...");
}
public interface ProcessListener {
public void charRead(BackgroundProcess process, char value);
public void lineRead(BackgroundProcess process, String text);
public void processFailed(BackgroundProcess process, Exception exp);
public void processCompleted(BackgroundProcess process);
}
public class BackgroundProcess extends Thread {
private List<String> commands;
private File startIn;
private int exitValue;
private ProcessListener listener;
private OutputQueue outputQueue;
public BackgroundProcess(String... cmds) {
commands = new ArrayList<>(Arrays.asList(cmds));
outputQueue = new OutputQueue(this);
}
public void setStartIn(File startIn) {
this.startIn = startIn;
}
public File getStartIn() {
return startIn;
}
public int getExitValue() {
return exitValue;
}
public void setListener(ProcessListener listener) {
this.listener = listener;
}
public ProcessListener getListener() {
return listener;
}
@Override
public void run() {
ProcessBuilder pb = new ProcessBuilder(commands);
File startIn = getStartIn();
if (startIn != null) {
pb.directory(startIn);
}
pb.redirectError();
Process p;
try {
p = pb.start();
InputStreamConsumer isc = new InputStreamConsumer(p.getInputStream(), this, getListener());
outputQueue.init(p.getOutputStream(), getListener());
outputQueue.start();
p.waitFor();
isc.join();
outputQueue.terminate();
outputQueue.join();
ProcessListener listener = getListener();
if (listener != null) {
listener.processCompleted(this);
}
} catch (InterruptedException ex) {
ProcessListener listener = getListener();
if (listener != null) {
listener.processFailed(this, ex);
}
} catch (IOException ex) {
ProcessListener listener = getListener();
if (listener != null) {
listener.processFailed(this, ex);
}
}
}
public void send(String cmd) {
outputQueue.send(cmd);
}
}
public class OutputQueue extends Thread {
private List<String> cmds;
private OutputStream os;
private ProcessListener listener;
private BackgroundProcess backgroundProcess;
private ReentrantLock waitLock;
private Condition waitCon;
private boolean keepRunning = true;
public OutputQueue(BackgroundProcess bp) {
backgroundProcess = bp;
cmds = new ArrayList<>(25);
waitLock = new ReentrantLock();
waitCon = waitLock.newCondition();
}
public ProcessListener getListener() {
return listener;
}
public OutputStream getOutputStream() {
return os;
}
public BackgroundProcess getBackgroundProcess() {
return backgroundProcess;
}
public void init(OutputStream outputStream, ProcessListener listener) {
os = outputStream;
this.listener = listener;
}
public void send(String cmd) {
waitLock.lock();
try {
cmds.add(cmd);
waitCon.signalAll();
} finally {
waitLock.unlock();
}
}
public void terminate() {
waitLock.lock();
try {
cmds.clear();
keepRunning = false;
waitCon.signalAll();
} finally {
waitLock.unlock();
}
}
@Override
public void run() {
try {
Thread.sleep(500);
} catch (InterruptedException ex) {
}
BackgroundProcess backgroundProcess = getBackgroundProcess();
ProcessListener listener = getListener();
OutputStream outputStream = getOutputStream();
try {
while (keepRunning) {
while (cmds.isEmpty() && keepRunning) {
waitLock.lock();
try {
waitCon.await();
} catch (Exception exp) {
} finally {
waitLock.unlock();
}
}
if (!cmds.isEmpty()) {
waitLock.lock();
try {
while (!cmds.isEmpty()) {
String cmd = cmds.remove(0);
System.out.println("Send " + cmd);
outputStream.write(cmd.getBytes());
outputStream.write('\n');
outputStream.write('\r');
outputStream.flush();
}
} finally {
waitLock.unlock();
}
}
}
} catch (IOException ex) {
if (listener != null) {
listener.processFailed(backgroundProcess, ex);
}
}
}
}
public class InputStreamConsumer extends Thread {
private InputStream is;
private ProcessListener listener;
private BackgroundProcess backgroundProcess;
public InputStreamConsumer(InputStream is, BackgroundProcess backgroundProcess, ProcessListener listener) {
this.is = is;
this.listener = listener;
this.backgroundProcess = backgroundProcess;
start();
}
public ProcessListener getListener() {
return listener;
}
public BackgroundProcess getBackgroundProcess() {
return backgroundProcess;
}
@Override
public void run() {
BackgroundProcess backgroundProcess = getBackgroundProcess();
ProcessListener listener = getListener();
try {
StringBuilder sb = new StringBuilder(64);
int in = -1;
while ((in = is.read()) != -1) {
char value = (char) in;
if (listener != null) {
listener.charRead(backgroundProcess, value);
if (value == '\n' || value == '\r') {
if (sb.length() > 0) {
listener.lineRead(null, sb.toString());
sb.delete(0, sb.length());
}
} else {
sb.append(value);
}
}
}
} catch (IOException ex) {
listener.processFailed(backgroundProcess, ex);
}
}
}
}