blocks|key|953576|text|对于Java7和更高版本的，请参阅Evgeniy+Dorofeev的answer。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|953577|对于Java6和更早版本的，请创建并使用StreamGobbler|CODE|953578|StreamGobbler+errorGobbler+=+
++new+StreamGobbler(p.getErrorStream(),+"ERROR");

//+any+output?
StreamGobbler+outputGobbler+=+
++new+StreamGobbler(p.getInputStream(),+"OUTPUT");

//+start+gobblers
outputGobbler.start();
errorGobbler.start();|code-block|syntax|javascript|953579|..。|953580|private+class+StreamGobbler+extends+Thread+{
++++InputStream+is;
++++String+type;

++++private+StreamGobbler(InputStream+is,+String+type)+{
++++++++this.is+=+is;
++++++++this.type+=+type;
++++}

++++@Override
++++public+void+run()+{
++++++++try+{
++++++++++++InputStreamReader+isr+=+new+InputStreamReader(is);
++++++++++++BufferedReader+br+=+new+BufferedReader(isr);
++++++++++++String+line+=+null;
++++++++++++while+((line+=+br.readLine())+!=+null)
++++++++++++++++System.out.println(type+%2B+">+"+%2B+line);
++++++++}
++++++++catch+(IOException+ioe)+{
++++++++++++ioe.printStackTrace();
++++++++}
++++}
}|953581|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/14168097/59087^0|2|B|Y|6|0|0|2|B|K|D|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@$9|12|A|13|1|14]]|E|$]]|$1|F|3|G|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|H]]|D|@]|E|$]]|$1|I|3|J|5|K|7|1A|8|@]|D|@]|E|$L|M]]|$1|N|3|O|5|6|7|1B|8|@]|D|@]|E|$]]|$1|P|3|Q|5|K|7|1C|8|@]|D|@]|E|$L|M]]|$1|R|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|S|$T|$5|U|V|W|E|$X|Y]]]]

For Java 7 and later, see Evgeniy Dorofeev's <a href="https://stackoverflow.com/a/14168097/59087">answer</a>.
For Java 6 and earlier, create and use a <code>StreamGobbler</code>:
<pre class="lang-java prettyprint-override"><code>StreamGobbler errorGobbler = 
 new StreamGobbler(p.getErrorStream(), &quot;ERROR&quot;);

// any output?
StreamGobbler outputGobbler = 
 new StreamGobbler(p.getInputStream(), &quot;OUTPUT&quot;);

// start gobblers
outputGobbler.start();
errorGobbler.start();
</code></pre>
...
<pre class="lang-java prettyprint-override"><code>private class StreamGobbler extends Thread {
 InputStream is;
 String type;

 private StreamGobbler(InputStream is, String type) {
 this.is = is;
 this.type = type;
 }

 @Override
 public void run() {
 try {
 InputStreamReader isr = new InputStreamReader(is);
 BufferedReader br = new BufferedReader(isr);
 String line = null;
 while ((line = br.readLine()) != null)
 System.out.println(type + &quot;&gt; &quot; + line);
 }
 catch (IOException ioe) {
 ioe.printStackTrace();
 }
 }
}
</code></pre>

blocks|key|4303218|text|使用ProcessBuilder.inheritIO，它将子进程标准I/O的源和目标设置为与当前Java进程的源和目标相同。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4303219|Process+p+=+new+ProcessBuilder().inheritIO().command("command1").start();|code-block|syntax|javascript|4303220|如果Java+7不是一个选项|4303221|public+static+void+main(String[]+args)+throws+Exception+{
++++Process+p+=+Runtime.getRuntime().exec("cmd+/c+dir");
++++inheritIO(p.getInputStream(),+System.out);
++++inheritIO(p.getErrorStream(),+System.err);

}

private+static+void+inheritIO(final+InputStream+src,+final+PrintStream+dest)+{
++++new+Thread(new+Runnable()+{
++++++++public+void+run()+{
++++++++++++Scanner+sc+=+new+Scanner(src);
++++++++++++while+(sc.hasNextLine())+{
++++++++++++++++dest.println(sc.nextLine());
++++++++++++}
++++++++}
++++}).start();
}|4303222|线程将在子进程结束时自动终止，因为src将EOF。|4303223|entityMap^0|2|O|0|0|0|0|H|3|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|R|$]]

Use <code>ProcessBuilder.inheritIO</code>, it sets the source and destination for subprocess standard I/O to be the same as those of the current Java process.

<pre><code>Process p = new ProcessBuilder().inheritIO().command("command1").start();
</code></pre>

If Java 7 is not an option

<pre><code>public static void main(String[] args) throws Exception {
 Process p = Runtime.getRuntime().exec("cmd /c dir");
 inheritIO(p.getInputStream(), System.out);
 inheritIO(p.getErrorStream(), System.err);

}

private static void inheritIO(final InputStream src, final PrintStream dest) {
 new Thread(new Runnable() {
 public void run() {
 Scanner sc = new Scanner(src);
 while (sc.hasNextLine()) {
 dest.println(sc.nextLine());
 }
 }
 }).start();
}
</code></pre>

Threads will die automatically when subprocess finishes, because <code>src</code> will EOF.

blocks|key|240909|text|我也只能使用Java+6，我使用了@EvgeniyDorofeev的线程扫描器实现。在我的代码中，在一个进程完成后，我必须立即执行另外两个进程，每个进程都比较重定向的输出(基于diff的单元测试，以确保stdout和stderr与受祝福的相同)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|240910|即使我用waitFor()来完成这个过程，扫描器线程也不会很快完成。为了使代码正常工作，我必须确保线程在进程完成后被联接。|240911|public+static+int+runRedirect+(String[]+args,+String+stdout_redirect_to,+String+stderr_redirect_to)+throws+IOException,+InterruptedException+{
++++ProcessBuilder+b+=+new+ProcessBuilder().command(args);
++++Process+p+=+b.start();
++++Thread+ot+=+null;
++++PrintStream+out+=+null;
++++if+(stdout_redirect_to+!=+null)+{
++++++++out+=+new+PrintStream(new+BufferedOutputStream(new+FileOutputStream(stdout_redirect_to)));
++++++++ot+=+inheritIO(p.getInputStream(),+out);
++++++++ot.start();
++++}
++++Thread+et+=+null;
++++PrintStream+err+=+null;
++++if+(stderr_redirect_to+!=+null)+{
++++++++err+=+new+PrintStream(new+BufferedOutputStream(new+FileOutputStream(stderr_redirect_to)));
++++++++et+=+inheritIO(p.getErrorStream(),+err);
++++++++et.start();
++++}
++++p.waitFor();++++//+ensure+the+process+finishes+before+proceeding
++++if+(ot+!=+null)
++++++++ot.join();++//+ensure+the+thread+finishes+before+proceeding
++++if+(et+!=+null)
++++++++et.join();++//+ensure+the+thread+finishes+before+proceeding
++++int+rc+=+p.exitValue();
++++return+rc;
}

private+static+Thread+inheritIO+(final+InputStream+src,+final+PrintStream+dest)+{
++++return+new+Thread(new+Runnable()+{
++++++++public+void+run()+{
++++++++++++Scanner+sc+=+new+Scanner(src);
++++++++++++while+(sc.hasNextLine())
++++++++++++++++dest.println(sc.nextLine());
++++++++++++dest.flush();
++++++++}
++++});
}|code-block|syntax|javascript|240912|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I too can use only Java 6. I used @EvgeniyDorofeev's thread scanner implementation. In my code, after a process finishes, I have to immediately execute two other processes that each compare the redirected output (a diff-based unit test to ensure stdout and stderr are the same as the blessed ones).

The scanner threads don't finish soon enough, even if I waitFor() the process to complete. To make the code work correctly, I have to make sure the threads are joined after the process finishes.

<pre><code>public static int runRedirect (String[] args, String stdout_redirect_to, String stderr_redirect_to) throws IOException, InterruptedException {
 ProcessBuilder b = new ProcessBuilder().command(args);
 Process p = b.start();
 Thread ot = null;
 PrintStream out = null;
 if (stdout_redirect_to != null) {
 out = new PrintStream(new BufferedOutputStream(new FileOutputStream(stdout_redirect_to)));
 ot = inheritIO(p.getInputStream(), out);
 ot.start();
 }
 Thread et = null;
 PrintStream err = null;
 if (stderr_redirect_to != null) {
 err = new PrintStream(new BufferedOutputStream(new FileOutputStream(stderr_redirect_to)));
 et = inheritIO(p.getErrorStream(), err);
 et.start();
 }
 p.waitFor(); // ensure the process finishes before proceeding
 if (ot != null)
 ot.join(); // ensure the thread finishes before proceeding
 if (et != null)
 et.join(); // ensure the thread finishes before proceeding
 int rc = p.exitValue();
 return rc;
}

private static Thread inheritIO (final InputStream src, final PrintStream dest) {
 return new Thread(new Runnable() {
 public void run() {
 Scanner sc = new Scanner(src);
 while (sc.hasNextLine())
 dest.println(sc.nextLine());
 dest.flush();
 }
 });
}
</code></pre>

blocks|key|953682|text|默认情况下，创建的子进程没有自己的终端或控制台。它的所有标准I/O操作(即stdin、stdout、stderr)都将被重定向到父进程，在父进程中可以通过使用方法getOutputStream()、getInputStream()和getErrorStream()获得的流来访问它们。父流程使用这些流将输入提供给子流程并从子流程获取输出。由于一些本机平台仅为标准输入流和输出流提供有限的缓冲区大小，因此未能及时写入输入流或读取子进程的输出流可能会导致子进程阻塞，甚至死锁。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|953683|https://www.securecoding.cert.org/confluence/display/java/FIO07-J.%2BDo%2Bnot%2Blet%2Bexternal%2Bprocesses%2Bblock%2Bon%2BIO%2Bbuffers|offset|length|953684|entityMap|0|LINK|mutability|MUTABLE|url|https://www.securecoding.cert.org/confluence/display/java/FIO07-J.%2BDo%2Bnot%2Blet%2Bexternal%2Bprocesses%2Bblock%2Bon%2BIO%2Bbuffers^0|0|0|38|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

By default, the created subprocess does not have its own terminal or console. All its standard I/O (i.e. stdin, stdout, stderr) operations will be redirected to the parent process, where they can be accessed via the streams obtained using the methods getOutputStream(), getInputStream(), and getErrorStream(). The parent process uses these streams to feed input to and get output from the subprocess. Because some native platforms only provide limited buffer size for standard input and output streams, failure to promptly write the input stream or read the output stream of the subprocess may cause the subprocess to block, or even deadlock.

<a href="https://www.securecoding.cert.org/confluence/display/java/FIO07-J.+Do+not+let+external+processes+block+on+IO+buffers" rel="nofollow">https://www.securecoding.cert.org/confluence/display/java/FIO07-J.+Do+not+let+external+processes+block+on+IO+buffers</a>

blocks|key|953801|text|使用Java8+lambda的灵活解决方案，允许您提供一个处理输出的Consumer+(例如，记录)逐行记录。run()是一个没有抛出检查异常的一行程序。作为实现Runnable的替代方案，它也可以像其他答案所建议的那样扩展Thread。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|953802|class+StreamGobbler+implements+Runnable+{
++++private+InputStream+inputStream;
++++private+Consumer<String>+consumeInputLine;

++++public+StreamGobbler(InputStream+inputStream,+Consumer<String>+consumeInputLine)+{
++++++++this.inputStream+=+inputStream;
++++++++this.consumeInputLine+=+consumeInputLine;
++++}

++++public+void+run()+{
++++++++new+BufferedReader(new+InputStreamReader(inputStream)).lines().forEach(consumeInputLine);
++++}
}|code-block|syntax|javascript|953803|然后，您可以像这样使用它：|953804|public+void+runProcessWithGobblers()+throws+IOException,+InterruptedException+{
++++Process+p+=+new+ProcessBuilder("...").start();
++++Logger+logger+=+LoggerFactory.getLogger(getClass());

++++StreamGobbler+outputGobbler+=+new+StreamGobbler(p.getInputStream(),+System.out::println);
++++StreamGobbler+errorGobbler+=+new+StreamGobbler(p.getErrorStream(),+logger::error);

++++new+Thread(outputGobbler).start();
++++new+Thread(errorGobbler).start();
++++p.waitFor();
}|953805|在这里，logger将输出流重定向到System.out，并在错误级别记录错误流。|953806|entityMap^0|Y|8|1J|5|29|8|34|6|0|0|0|0|4|6|I|A|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|14|8|@$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|19|8|@]|D|@]|E|$]]]|R|$]]

A flexible solution with Java 8 lambda that lets you provide a <code>Consumer</code> that will process the output (eg. log it) line by line. <code>run()</code> is a one-liner with no checked exceptions thrown. Alternatively to implementing <code>Runnable</code>, it can extend <code>Thread</code> instead as other answers suggest.

<pre><code>class StreamGobbler implements Runnable {
 private InputStream inputStream;
 private Consumer&lt;String&gt; consumeInputLine;

 public StreamGobbler(InputStream inputStream, Consumer&lt;String&gt; consumeInputLine) {
 this.inputStream = inputStream;
 this.consumeInputLine = consumeInputLine;
 }

 public void run() {
 new BufferedReader(new InputStreamReader(inputStream)).lines().forEach(consumeInputLine);
 }
}
</code></pre>

You can then use it for example like this:

<pre><code>public void runProcessWithGobblers() throws IOException, InterruptedException {
 Process p = new ProcessBuilder("...").start();
 Logger logger = LoggerFactory.getLogger(getClass());

 StreamGobbler outputGobbler = new StreamGobbler(p.getInputStream(), System.out::println);
 StreamGobbler errorGobbler = new StreamGobbler(p.getErrorStream(), logger::error);

 new Thread(outputGobbler).start();
 new Thread(errorGobbler).start();
 p.waitFor();
}
</code></pre>

Here the output stream is redirected to <code>System.out</code> and the error stream is logged on the error level by the <code>logger</code>.

blocks|key|241758|text|它很简单，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|241759|++++File+logFile+=+new+File(...);
++++ProcessBuilder+pb+=+new+ProcessBuilder()
++++++++.command("somecommand",+"arg1",+"arg2")
++++processBuilder.redirectErrorStream(true);
++++processBuilder.redirectOutput(logFile);|code-block|syntax|javascript|241760|通过.redirectErrorStream(true)，您可以告诉process合并错误和输出流，然后通过.redirectOutput()，您可以将合并的输出重定向到一个文件。|offset|length|style|BOLD|241761|更新：|241762|我做到了以下几点：|241763|public+static+void+main(String[]+args)+{
++++//+Async+part
++++Runnable+r+=+()+->+{
++++++++ProcessBuilder+pb+=+new+ProcessBuilder().command("...");
++++++++//+Merge+System.err+and+System.out
++++++++pb.redirectErrorStream(true);
++++++++//+Inherit+System.out+as+redirect+output+stream
++++++++pb.redirectOutput(ProcessBuilder.Redirect.INHERIT);
++++++++try+{
++++++++++++pb.start();
++++++++}+catch+(IOException+e)+{
++++++++++++e.printStackTrace();
++++++++}
++++};
++++new+Thread(r,+"asyncOut").start();
++++//+here+goes+your+main+part
}|241764|现在，您可以在System.out中看到主线程和asyncOut线程的输出|241765|entityMap^0|0|0|1Y|K|0|0|3|0|0|9|0|0|0|11|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@$I|12|J|13|K|L]]|9|@]|A|$]]|$1|O|3|P|5|6|7|14|8|@$I|15|J|16|K|L]]|9|@]|A|$]]|$1|Q|3|R|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|18|8|@$I|19|J|1A|K|L]]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|V|$]]

It's as simple as following:

<pre><code> File logFile = new File(...);
 ProcessBuilder pb = new ProcessBuilder()
 .command("somecommand", "arg1", "arg2")
 processBuilder.redirectErrorStream(true);
 processBuilder.redirectOutput(logFile);
</code></pre>

by .redirectErrorStream(true) you tell process to merge error and output stream and then by .redirectOutput(file) you redirect merged output to a file. 

Update:

I did manage to do this as follows:

<pre><code>public static void main(String[] args) {
 // Async part
 Runnable r = () -&gt; {
 ProcessBuilder pb = new ProcessBuilder().command("...");
 // Merge System.err and System.out
 pb.redirectErrorStream(true);
 // Inherit System.out as redirect output stream
 pb.redirectOutput(ProcessBuilder.Redirect.INHERIT);
 try {
 pb.start();
 } catch (IOException e) {
 e.printStackTrace();
 }
 };
 new Thread(r, "asyncOut").start();
 // here goes your main part
}
</code></pre>

Now you're able to see both outputs from main and asyncOut threads in System.out

blocks|key|241032|text|Thread+thread+=+new+Thread(()+->+{
++++++new+BufferedReader(
++++++++++new+InputStreamReader(inputStream,+
++++++++++++++++++++++++++++++++StandardCharsets.UTF_8))
++++++++++++++.lines().forEach(...);
++++});
++++thread.start();|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|241033|您的自定义代码将替换为...|unstyled|offset|length|style|CODE|241034|entityMap^0|0|B|3|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>Thread thread = new Thread(() -&gt; {
 new BufferedReader(
 new InputStreamReader(inputStream, 
 StandardCharsets.UTF_8))
 .lines().forEach(...);
 });
 thread.start();
</code></pre>

Your custom code goes instead of the <code>...</code>

blocks|key|241036|text|使用CompletableFuture捕获输出和反应处理的简单java8解决方案|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|241037|static+CompletableFuture<String>+readOutStream(InputStream+is)+{
++++return+CompletableFuture.supplyAsync(()+->+{
++++++++try+(
++++++++++++++++InputStreamReader+isr+=+new+InputStreamReader(is);
++++++++++++++++BufferedReader+br+=+new+BufferedReader(isr);
++++++++)+{
++++++++++++++StringBuilder+res+=+new+StringBuilder();
++++++++++++++String+inputLine;
++++++++++++++while+((inputLine+=+br.readLine())+!=+null)+{
++++++++++++++++++res.append(inputLine).append(System.lineSeparator());
++++++++++++++}
++++++++++++++return+res.toString();
++++++++}+catch+(Throwable+e)+{
++++++++++++throw+new+RuntimeException("problem+with+executing+program",+e);
++++++++}
++++});
}|code-block|syntax|javascript|241038|和用法：|241039|Process+p+=+Runtime.getRuntime().exec(cmd);
CompletableFuture<String>+soutFut+=+readOutStream(p.getInputStream());
CompletableFuture<String>+serrFut+=+readOutStream(p.getErrorStream());
CompletableFuture<String>+resultFut+=+
++++soutFut.thenCombine(serrFut,+(stdout,+stderr)+->+{
+++++++++//+print+to+current+stderr+the+stderr+of+process+and+return+the+stdout
+++++++++System.err.println(stderr);
++++++++
+++++++++return+stdout;
++++});
//+get+stdout+once+ready,+blocking
String+result+=+resultFut.get();|241040|entityMap^0|2|H|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

Simple java8 solution with capturing both outputs and reactive processing using <code>CompletableFuture</code>:
<pre><code>static CompletableFuture&lt;String&gt; readOutStream(InputStream is) {
 return CompletableFuture.supplyAsync(() -&gt; {
 try (
 InputStreamReader isr = new InputStreamReader(is);
 BufferedReader br = new BufferedReader(isr);
 ) {
 StringBuilder res = new StringBuilder();
 String inputLine;
 while ((inputLine = br.readLine()) != null) {
 res.append(inputLine).append(System.lineSeparator());
 }
 return res.toString();
 } catch (Throwable e) {
 throw new RuntimeException(&quot;problem with executing program&quot;, e);
 }
 });
}
</code></pre>
And the usage:
<pre><code>Process p = Runtime.getRuntime().exec(cmd);
CompletableFuture&lt;String&gt; soutFut = readOutStream(p.getInputStream());
CompletableFuture&lt;String&gt; serrFut = readOutStream(p.getErrorStream());
CompletableFuture&lt;String&gt; resultFut = 
 soutFut.thenCombine(serrFut, (stdout, stderr) -&gt; {
 // print to current stderr the stderr of process and return the stdout
 System.err.println(stderr);
 
 return stdout;
 });
// get stdout once ready, blocking
String result = resultFut.get();
</code></pre>

blocks|key|4785812|text|作为对msangel+answer的补充，我想添加以下代码块：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4785813|private+static+CompletableFuture<Boolean>+redirectToLogger(final+InputStream+inputStream,+final+Consumer<String>+logLineConsumer)+{
++++++++return+CompletableFuture.supplyAsync(()+->+{
++++++++++++try+(
++++++++++++++++InputStreamReader+inputStreamReader+=+new+InputStreamReader(inputStream);
++++++++++++++++BufferedReader+bufferedReader+=+new+BufferedReader(inputStreamReader);
++++++++++++)+{
++++++++++++++++String+line+=+null;
++++++++++++++++while((line+=+bufferedReader.readLine())+!=+null)+{
++++++++++++++++++++logLineConsumer.accept(line);
++++++++++++++++}
++++++++++++++++return+true;
++++++++++++}+catch+(IOException+e)+{
++++++++++++++++return+false;
++++++++++++}
++++++++});
++++}|code-block|syntax|javascript|4785814|它允许将进程的输入流(stdout、stderr)重定向到其他使用者。这可能是System.out::println或任何其他消耗字符串的内容。|4785815|用法：|4785816|...
Process+process+=+processBuilder.start()
CompletableFuture<Boolean>+stdOutRes+=+redirectToLogger(process.getInputStream(),+System.out::println);
CompletableFuture<Boolean>+stdErrRes+=+redirectToLogger(process.getErrorStream(),+System.out::println);
System.out.println(stdOutRes.get());
System.out.println(stdErrRes.get());
System.out.println(process.waitFor());|4785817|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/57483714/2019601^0|B|6|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|C|$]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|C|$]]|$1|M|3|N|5|F|7|13|8|@]|9|@]|C|$G|H]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

As an addition to msangel <a href="https://stackoverflow.com/a/57483714/2019601">answer</a> I would like to add the following code block: 

<pre><code>private static CompletableFuture&lt;Boolean&gt; redirectToLogger(final InputStream inputStream, final Consumer&lt;String&gt; logLineConsumer) {
 return CompletableFuture.supplyAsync(() -&gt; {
 try (
 InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
 BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
 ) {
 String line = null;
 while((line = bufferedReader.readLine()) != null) {
 logLineConsumer.accept(line);
 }
 return true;
 } catch (IOException e) {
 return false;
 }
 });
 }
</code></pre>

It allows to redirect the input stream (stdout, stderr) of the process to some other consumer. This might be System.out::println or anything else consuming strings.

Usage:

<pre><code>...
Process process = processBuilder.start()
CompletableFuture&lt;Boolean&gt; stdOutRes = redirectToLogger(process.getInputStream(), System.out::println);
CompletableFuture&lt;Boolean&gt; stdErrRes = redirectToLogger(process.getErrorStream(), System.out::println);
System.out.println(stdOutRes.get());
System.out.println(stdErrRes.get());
System.out.println(process.waitFor());
</code></pre>

blocks|key|954081|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|954082|下面是使用zt-exec而不是ProcessBuilder的代码：|954083|添加依赖项：|954084|<dependency>
++<groupId>org.zeroturnaround</groupId>
++<artifactId>zt-exec</artifactId>
++<version>1.11</version>
</dependency>|code-block|syntax|javascript|954085|代码：|954086|new+ProcessExecutor()
++.command("somecommand",+"arg1",+"arg2")
++.redirectOutput(System.out)
++.redirectError(System.err)
++.execute();|954087|该库的文档在此处：https://github.com/zeroturnaround/zt-exec/|offset|length|954088|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/zeroturnaround/zt-exec/^0|0|0|0|0|0|0|9|16|0|0^^$0|@$1|2|3|-4|4|5|6|Z|7|@]|8|@]|9|$]]|$1|A|3|B|4|5|6|10|7|@]|8|@]|9|$]]|$1|C|3|D|4|5|6|11|7|@]|8|@]|9|$]]|$1|E|3|F|4|G|6|12|7|@]|8|@]|9|$H|I]]|$1|J|3|K|4|5|6|13|7|@]|8|@]|9|$]]|$1|L|3|M|4|G|6|14|7|@]|8|@]|9|$H|I]]|$1|N|3|O|4|5|6|15|7|@]|8|@$P|16|Q|17|1|18]]|9|$]]|$1|R|3|-4|4|5|6|19|7|@]|8|@]|9|$]]]|S|$T|$4|U|V|W|9|$X|Y]]]]

There is a library that provides a better ProcessBuilder, zt-exec. This library can do exactly what you are asking for and more.

Here's what your code would look like with zt-exec instead of ProcessBuilder : 

add the dependency :

<pre><code>&lt;dependency&gt;
 &lt;groupId&gt;org.zeroturnaround&lt;/groupId&gt;
 &lt;artifactId&gt;zt-exec&lt;/artifactId&gt;
 &lt;version&gt;1.11&lt;/version&gt;
&lt;/dependency&gt;
</code></pre>

The code : 

<pre><code>new ProcessExecutor()
 .command("somecommand", "arg1", "arg2")
 .redirectOutput(System.out)
 .redirectError(System.err)
 .execute();
</code></pre>

Documentation of the library is here : <a href="https://github.com/zeroturnaround/zt-exec/" rel="nofollow noreferrer">https://github.com/zeroturnaround/zt-exec/</a>

blocks|key|241142|text|import+java.io.BufferedReader;
import+java.io.InputStreamReader;

public+class+Main+{

++++public+static+void+main(String[]+args)+throws+Exception+{
++++++++ProcessBuilder+pb+=+new+ProcessBuilder("script.bat");
++++++++pb.redirectErrorStream(true);
++++++++Process+p+=+pb.start();
++++++++BufferedReader+logReader+=+new+BufferedReader(new+InputStreamReader(p.getInputStream()));
++++++++String+logLine+=+null;
++++++++while+(+(logLine+=+logReader.readLine())+!=+null)+{
+++++++++++System.out.println("Script+output:+"+%2B+logLine);
++++++++}
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|241143|通过使用这一行：pb.redirectErrorStream(true);，我们可以组合InputStream和ErrorStream|unstyled|offset|length|style|CODE|241144|entityMap^0|0|8|T|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {

 public static void main(String[] args) throws Exception {
 ProcessBuilder pb = new ProcessBuilder(&quot;script.bat&quot;);
 pb.redirectErrorStream(true);
 Process p = pb.start();
 BufferedReader logReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
 String logLine = null;
 while ( (logLine = logReader.readLine()) != null) {
 System.out.println(&quot;Script output: &quot; + logLine);
 }
 }
}
</code></pre>
By using this line: <code>pb.redirectErrorStream(true);</code> we can combine InputStream and ErrorStream

blocks|key|4786215|text|我真的很惊讶，ProcessBuilder中的重定向方法不接受OutputStream，只接受File。这是Java强迫您编写强制样板代码的另一个证据。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4786216|也就是说，让我们看一看综合选项的列表：|4786217|4786218|如果您希望进程输出仅重定向到其父进程的输出流，inheritIO将完成此工作。|ordered-list-item|4786219|如果您希望进程输出转到文件中，请使用redirect*(file).|4786220|If如果您希望进程输出转到记录器，则需要在单独的线程中使用进程InputStream。查看使用Runnable或CompletableFuture的答案。|4786221|4786222|static+int+execute(List<String>+args,+PrintWriter+out)+{
++++ProcessBuilder+builder+=+new+ProcessBuilder()
++++++++++++.command(args)
++++++++++++.redirectErrorStream(true);
++++Process+process+=+null;
++++boolean+complete+=+false;
++++try+{
++++++++process+=+builder.start();
++++++++redirectOut(process.getInputStream(),+out)
++++++++++++++++.orTimeout(TIMEOUT,+TimeUnit.SECONDS);
++++++++complete+=+process.waitFor(TIMEOUT,+TimeUnit.SECONDS);
++++}+catch+(IOException+e)+{
++++++++throw+new+UncheckedIOException(e);
++++}+catch+(InterruptedException+e)+{
++++++++LOG.warn("Thread+was+interrupted",+e);
++++}+finally+{
++++++++if+(process+!=+null+&&+!complete)+{
++++++++++++LOG.warn("Process+{}+didn't+finish+within+{}+seconds",+args.get(0),+TIMEOUT);
++++++++++++process+=+process.destroyForcibly();
++++++++}
++++}

++++return+process+!=+null+?+process.exitValue()+:+1;
}

private+static+CompletableFuture<Void>+redirectOut(InputStream+in,+PrintWriter+out)+{
++++return+CompletableFuture.runAsync(()+->+{
++++++++try+(
++++++++++++++++InputStreamReader+inputStreamReader+=+new+InputStreamReader(in);
++++++++++++++++BufferedReader+bufferedReader+=+new+BufferedReader(inputStreamReader)
++++++++)+{
++++++++++++bufferedReader.lines()
++++++++++++++++++++.forEach(out::println);
++++++++}+catch+(IOException+e)+{
++++++++++++LOG.error("Failed+to+redirect+process+output",+e);
++++++++}
++++});
}|code-block|syntax|javascript|4786223|到目前为止，上面的代码相对于其他答案的优势：|4786224|4786225|redirectErrorStream(true)将错误流重定向到输出流，这样我们就只需要处理从ForkJoinPool运行的one.|4786226|CompletableFuture.runAsync。注意，这段代码不会通过在CompletableFuture上调用get或join来阻塞，而是在其完成时设置一个超时(Java+9%2B)。没有必要使用CompletableFuture.supplyAsync，因为从方法中实际上没有什么可返回的，redirectOut.|4786227|BufferedReader.lines比使用while循环更简单。|4786228|4786229|entityMap^0|7|E|V|C|1B|4|0|0|0|N|9|0|I|F|0|V|B|1B|8|1K|H|0|0|0|0|0|0|P|1C|C|0|0|Q|13|H|1N|3|1R|4|2S|T|44|B|0|0|K|N|5|0|0^^$0|@$1|2|3|4|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1E|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]|$1|I|3|J|5|K|7|1G|8|@$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|L|3|M|5|K|7|1J|8|@$9|1K|A|1L|B|C]]|D|@]|E|$]]|$1|N|3|O|5|K|7|1M|8|@$9|1N|A|1O|B|C]|$9|1P|A|1Q|B|C]|$9|1R|A|1S|B|C]]|D|@]|E|$]]|$1|P|3|-4|5|6|7|1T|8|@]|D|@]|E|$]]|$1|Q|3|R|5|S|7|1U|8|@]|D|@]|E|$T|U]]|$1|V|3|W|5|6|7|1V|8|@]|D|@]|E|$]]|$1|X|3|-4|5|6|7|1W|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|K|7|1X|8|@$9|1Y|A|1Z|B|C]|$9|20|A|21|B|C]]|D|@]|E|$]]|$1|10|3|11|5|K|7|22|8|@$9|23|A|24|B|C]|$9|25|A|26|B|C]|$9|27|A|28|B|C]|$9|29|A|2A|B|C]|$9|2B|A|2C|B|C]|$9|2D|A|2E|B|C]]|D|@]|E|$]]|$1|12|3|13|5|K|7|2F|8|@$9|2G|A|2H|B|C]|$9|2I|A|2J|B|C]]|D|@]|E|$]]|$1|14|3|-4|5|6|7|2K|8|@]|D|@]|E|$]]|$1|15|3|-4|5|6|7|2L|8|@]|D|@]|E|$]]]|16|$]]

It's really surprising to me that the redirection methods in <code>ProcessBuilder</code> don't accept an <code>OutputStream</code>, only <code>File</code>. Yet another proof of forced boilerplate code that Java forces you to write.
That said, let's look at a list of comprehensive options:
<ol>
<li>If you want the process output to simply be redirected to its parent's output stream, <code>inheritIO</code> will do the job.</li>
<li>If you want the process output to go to a file, use <code>redirect*(file)</code>.</li>
<li>If you want the process output to go to a logger, you need to consume the process <code>InputStream</code> in a separate thread. See the answers that use a <code>Runnable</code> or <code>CompletableFuture</code>. You can also adapt the code below to do this.</li>
<li>If you want to the process output to go to a <code>PrintWriter</code>, that may or may not be the stdout (very useful for testing), you can do the following:</li>
</ol>
<pre><code>static int execute(List&lt;String&gt; args, PrintWriter out) {
 ProcessBuilder builder = new ProcessBuilder()
 .command(args)
 .redirectErrorStream(true);
 Process process = null;
 boolean complete = false;
 try {
 process = builder.start();
 redirectOut(process.getInputStream(), out)
 .orTimeout(TIMEOUT, TimeUnit.SECONDS);
 complete = process.waitFor(TIMEOUT, TimeUnit.SECONDS);
 } catch (IOException e) {
 throw new UncheckedIOException(e);
 } catch (InterruptedException e) {
 LOG.warn(&quot;Thread was interrupted&quot;, e);
 } finally {
 if (process != null &amp;&amp; !complete) {
 LOG.warn(&quot;Process {} didn't finish within {} seconds&quot;, args.get(0), TIMEOUT);
 process = process.destroyForcibly();
 }
 }

 return process != null ? process.exitValue() : 1;
}

private static CompletableFuture&lt;Void&gt; redirectOut(InputStream in, PrintWriter out) {
 return CompletableFuture.runAsync(() -&gt; {
 try (
 InputStreamReader inputStreamReader = new InputStreamReader(in);
 BufferedReader bufferedReader = new BufferedReader(inputStreamReader)
 ) {
 bufferedReader.lines()
 .forEach(out::println);
 } catch (IOException e) {
 LOG.error(&quot;Failed to redirect process output&quot;, e);
 }
 });
}
</code></pre>
Advantages of the code above over the other answers thus far:
<ol>
<li><code>redirectErrorStream(true)</code> redirects the error stream to the output stream, so that we only have to bother with one.</li>
<li><code>CompletableFuture.runAsync</code> runs from the <code>ForkJoinPool</code>. Note that this code doesn't block by calling <code>get</code> or <code>join</code> on the <code>CompletableFuture</code> but sets a timeout instead on its completion (Java 9+). There's no need for <code>CompletableFuture.supplyAsync</code> because there's nothing really to return from the method <code>redirectOut</code>.</li>
<li><code>BufferedReader.lines</code> is simpler than using a <code>while</code> loop.</li>
</ol>

I'm building a process in Java using ProcessBuilder as follows:

<pre><code>ProcessBuilder pb = new ProcessBuilder()
 .command("somecommand", "arg1", "arg2")
 .redirectErrorStream(true);
Process p = pb.start();

InputStream stdOut = p.getInputStream();
</code></pre>

Now my problem is the following: I would like to capture whatever is going through stdout and/or stderr of that process and redirect it to <code>System.out</code> asynchronously. I want the process and its output redirection to run in the background. So far, the only way I've found to do this is to manually spawn a new thread that will continuously read from <code>stdOut</code> and then call the appropriate <code>write()</code> method of <code>System.out</code>. 

<pre><code>new Thread(new Runnable(){
 public void run(){
 byte[] buffer = new byte[8192];
 int len = -1;
 while((len = stdOut.read(buffer)) &gt; 0){
 System.out.write(buffer, 0, len);
 }
 }
}).start();
</code></pre>

While that approach kind of works, it feels a bit dirty. And on top of that, it gives me one more thread to manage and terminate correctly. Is there any better way to do this?

ProcessBuilder: Forwarding stdout and stderr of started processes without blocking the main thread

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在使用ProcessBuilder在Java中构建一个进程，如下所示：ProcessBuilder pb = new ProcessBuilder()        .command("somecommand", "arg1", "arg2")        .redirectErrorStream(true);P...

问ProcessBuilder:在不阻塞主线程的情况下转发已启动进程的标准输出和标准错误
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问ProcessBuilder:在不阻塞主线程的情况下转发已启动进程的标准输出和标准错误EN