Java process.getInputStream() 没有任何内容可读取，子进程死锁

发布于 2024-09-24 09:39:54 字数 1324 浏览 1 评论 0原文

我在某些进程包装方面遇到问题，并且该问题仅发生在 Windows XP 中。这段代码在 Windows 7 中完美运行。我真的很困惑为什么 XP 中的流是空的。我也尝试过使用 Process.Exec() 的 String[] 版本，但没有什么区别。

我正在使用以下类从进程的 STDOUT 和 STDERR （每个流的一个实例）中读取：


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

public class ThreadedStreamReader extends Thread{
 InputStream in;
 Queue messageQueue;

 public ThreadedStreamReader(InputStream s, Queue q)
 {
  in = s;
  messageQueue = q;
 }

 public void run()
 {
  try
  {
   BufferedReader r = new BufferedReader(new InputStreamReader(in));
   String line = null;
   while((line = r.readLine()) != null)
   {
    synchronized(messageQueue)
    {
     messageQueue.add(line);
    }
   }

  }catch(Exception e)
  {
   System.err.println("Bad things happened while reading from a stream");
  }
 }
}

我在这里使用它：


Process p = Runtime.getRuntime().exec("test.exe");
Queue<String> q = new LinkedList<String>();

ThreadedStreamReader stdout = new ThreadedStreamReader(p.getInputStream(), q);
ThreadedStreamReader stderr = new ThreadedStreamReader(p.getErrorStream(), q);

stdout.start();
stderr.start();

while(true)
{
    while(q.size() > 0)
    {
        System.out.println(q.remove());
    }
}

有人有任何想法吗？谢谢！

编辑：添加同步

编辑：就像更新一样，父流读取器的读取操作被阻止。如果我使用任务管理器终止子进程，它们会从流的关闭中读取空值。

原文

I am having an issue with some process wrapping, and it's only occurring in Windows XP. This code works perfectly in Windows 7. I'm really stumped as to why the streams are empty in XP. I've also tried using the String[] version of Process.Exec() and it made no difference.

I am using the following class to read from the process' STDOUT and STDERR (an instance for each stream):


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

public class ThreadedStreamReader extends Thread{
 InputStream in;
 Queue messageQueue;

 public ThreadedStreamReader(InputStream s, Queue q)
 {
  in = s;
  messageQueue = q;
 }

 public void run()
 {
  try
  {
   BufferedReader r = new BufferedReader(new InputStreamReader(in));
   String line = null;
   while((line = r.readLine()) != null)
   {
    synchronized(messageQueue)
    {
     messageQueue.add(line);
    }
   }

  }catch(Exception e)
  {
   System.err.println("Bad things happened while reading from a stream");
  }
 }
}

And I use it here:


Process p = Runtime.getRuntime().exec("test.exe");
Queue<String> q = new LinkedList<String>();

ThreadedStreamReader stdout = new ThreadedStreamReader(p.getInputStream(), q);
ThreadedStreamReader stderr = new ThreadedStreamReader(p.getErrorStream(), q);

stdout.start();
stderr.start();

while(true)
{
    while(q.size() > 0)
    {
        System.out.println(q.remove());
    }
}

Anyone have any ideas? Thanks!

Edit: Added synchronization

Edit: Just as an update, the parent stream readers are blocked on their read operation. If I kill the child processes, with the task manager, they read in the null from the closing of the stream.

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