在Java 6中使用继承的stdin / stdout / stderr启动进程

If I start a process via Java's ProcessBuilder class, I have full access to that process's standard in, standard out, and standard error streams as Java InputStreams and OutputStreams. However, I can't find a way to seamlessly connect those streams to System.in, System.out, and System.err.

如果我通过Java的ProcessBuilder类启动一个进程,我可以完全访问该进程的标准输入,标准输出和标准错误流,如Java InputStreams和OutputStreams。但是,我找不到将这些流无缝连接到System.in,System.out和System.err的方法。

It's possible to use redirectErrorStream() to get a single InputStream that contains the subprocess's standard out and standard error, and just loop through that and send it through my standard out—but I can't find a way to do that and let the user type into the process, as he or she could if I used the C system() call.

可以使用redirectErrorStream()来获取包含子进程的标准输出和标准错误的单个InputStream,然后循环遍历并通过我的标准输出 - 但我找不到一种方法来做到这一点并让用户如果我使用C系统()调用,他或她可以输入进程。

This appears to be possible in Java SE 7 when it comes out—I'm just wondering if there's a workaround now. Bonus points if the result of isatty() in the child process carries through the redirection.

这在Java SE 7出现时似乎是可能的 - 我只是想知道现在是否有解决方法。如果子进程中isatty()的结果通过重定向,则加分。

3 个解决方案

#1

You will need to copy the Process out, err, and input streams to the System versions. The easiest way to do that is using the IOUtils class from the Commons IO package. The copy method looks to be what you need. The copy method invocations will need to be in separate threads.

您需要将Process out,err和输入流复制到System版本。最简单的方法是使用Commons IO软件包中的IOUtils类。复制方法看起来就是您所需要的。复制方法调用需要在单独的线程中。

Here is the basic code:

这是基本代码:

// Assume you already have a processBuilder all configured and ready to go
final Process process = processBuilder.start();
new Thread(new Runnable() {public void run() {
  IOUtils.copy(process.getOutputStream(), System.out);
} } ).start();
new Thread(new Runnable() {public void run() {
  IOUtils.copy(process.getErrorStream(), System.err);
} } ).start();
new Thread(new Runnable() {public void run() {
  IOUtils.copy(System.in, process.getInputStream());
} } ).start();

#2

A variation on John's answer that compiles and doesn't require you to use Commons IO:

John的答案的一个变体,编译并且不要求您使用Commons IO:

private static void pipeOutput(Process process) {
    pipe(process.getErrorStream(), System.err);
    pipe(process.getInputStream(), System.out);
}

private static void pipe(final InputStream src, final PrintStream dest) {
    new Thread(new Runnable() {
        public void run() {
            try {
                byte[] buffer = new byte[1024];
                for (int n = 0; n != -1; n = src.read(buffer)) {
                    dest.write(buffer, 0, n);
                }
            } catch (IOException e) { // just exit
            }
        }
    }).start();
}

#3

For System.in use the following pipein() instead of pipe()

对于System.in,使用以下pipein()而不是pipe()

pipein(System.in, p.getOutputStream());

Implementation:

private static void pipein(final InputStream src, final OutputStream dest) {

    new Thread(new Runnable() {
        public void run() {
            try {
               int ret = -1;
               while ((ret = System.in.read()) != -1) {
                  dest.write(ret);
                  dest.flush();
               }
            } catch (IOException e) { // just exit
            }
        }
    }).start();

}

#1