Java启动Node.js程序立即关闭
问题描述:
我正在尝试制作一个带有Java FXML接口以及用于制作音频播放机器人的Node.js程序的Discord机器人。Java启动Node.js程序立即关闭
当我尝试打开Java内的Node.js进程时,我注意到它立即关闭,因为当我尝试写入时,出现IOException pipes are being closed
。我不确定为什么会发生这种情况,因为当我在命令行中运行节点时,它完全保持打开状态。有谁知道我的程序为什么立即关闭?
Node.js的通信类:
public class NodeCommunicationHandler {
private static final Logger LOG = Logger.getLogger(NodeCommunicationHandler.class.getName());
private Process nodeProcess;
private ExecutorService threadPool;
private ProcessHandlerTask callbackHandler;
private StringProperty callback;
private OutputStream writeStream;
/**
*
*/
public NodeCommunicationHandler() {
try {
// Activate Node.js sub-process
this.nodeProcess = new ProcessBuilder("cmd", "/c", "start", "node", "\"" + Reference.NODE_PROGRAM_LOCATION + "\"").start();
// Initialize the stdout writing stream
this.writeStream = this.nodeProcess.getOutputStream();
// Initialize the stdin reader on the process
this.callbackHandler = new ProcessHandlerTask(this.nodeProcess);
// Bind the callback data from the process to the callback property
this.callback = new SimpleStringProperty();
this.callback.bind(this.callbackHandler.messageProperty());
// Run the thread of the process callback handler
this.threadPool = Executors.newFixedThreadPool(2);
this.threadPool.submit(this.callbackHandler);
} catch (IOException ex) {
NodeCommunicationHandler.LOG.log(Level.SEVERE, null, ex);
}
}
/**
* Retrieve the internal process callback.
*
* @return The callback.
*/
public StringProperty getCallback() {
return this.callback;
}
/**
* Writes a string command to the Node.js process.
*
* @param command The command to write.
*/
public void write(String command) {
try {
this.writeStream.write(command.getBytes());
this.writeStream.flush();
} catch (IOException ex) {
NodeCommunicationHandler.LOG.log(Level.SEVERE, null, ex);
}
}
/**
* Stop the Node.js process
*/
public void stop() {
try {
// Write the command STOP towards the node process to promptly exit the discord API.
this.write("STOP");
// Close the writing stream since STOP is the last command we have to write.
this.writeStream.close();
// Wait for the Node.js acknowledgement of the STOP issue.
NodeProcessExitHandler exitCond = new NodeProcessExitHandler(this.callback);
this.threadPool.submit(exitCond).get();
// Unbind the callback listener.
this.callback.unbind();
// Stop the callback handler and let the thread finish.
this.callbackHandler.stop();
// Keep the process alive until the callback handler has been disconnected.
this.threadPool.awaitTermination(10000, TimeUnit.MILLISECONDS);
// Kill the subprocess since we know
this.nodeProcess.destroy();
} catch (IOException | InterruptedException | ExecutionException ex) {
NodeCommunicationHandler.LOG.log(Level.SEVERE, null, ex);
}
}
}
而且我的JavaScript程序:
var stdin = process.openStdin();
stdin.addListener("data", function(d) {
console.log("You entered: " + d.toString());
});
的JavaScript是很基本的,但它应该能够提供我所需要的。
编辑:
问题描述中的小错误。 当进程以Java运行时,它会打开一个控制台窗口,并且Node程序实际上保持运行,但Outputstream只是断开连接并引发IOException。
答
第二天我启动应用程序并且该进程能够连接和发送数据,问题自动解决。我不知道是什么原因导致它不能在第一时间工作。