通过Java终端通过外部程序执行 [英] Execute external program through terminal in Java

问题描述

我有一个外部程序 Otter 作为参数获取了一些文件名并创建了一个输出文件，也指定为参数. 因此，例如，如果我的输入是"proof.in"，并且我希望将输出放置在"proof.out"文件中，则可以在终端中运行以下命令:

I have an external program Otter that gets as parameter some filename and creates an output file, also specified as parameter. So for example if my input is "proof.in" and I want my output to be placed in the "proof.out" file, I run the following command in the terminal:

otter <proof.in >proof.out

"proof.in"文件必须与水獭可执行文件位于同一文件中.

The "proof.in" file must be in the same file as the otter executable.

问题是我需要Java提供此功能，因此在Java代码中，我需要执行以下操作:

The problem is that I need this functionality from Java so in my Java code I do the following:

java.lang.Runtime.getRuntime().exec("otter <proof.in >proof.out")

但是在这一行之后，整个UI被冻结，什么也没有发生，并且没有生成输出文件.

but after this line the whole UI is frozen and nothing happens and no output file is generated.

有人可以告诉我我错了吗?

Could anyone show me where I got it wrong??

预先感谢， 塔玛什(Tamash)

Thanks in advance, Tamash

推荐答案

这是正常现象:您正在尝试启动通常由Shell发出的命令.

This is normal: you are attempting to launch a command normally issued by a shell.

在这里，<proof.in和>proof.out被当作otter可执行文件的原义参数，而不是shell重定向.但是查看该工具的主页将无法正常工作:它需要标准重定向上通常提供的stdin上的数据.

Here, <proof.in and >proof.out are taken as literal arguments to the otter executable, and not shell redirections. But seeing the home page for this tool, it will not work: it expects data on stdin, which the redirect normally provides.

您需要通过外壳(最好使用流程构建器)启动此命令:

You need to launch this command via a shell, and preferably using a process builder:

final ProcessBuilder pb = new ProcessBuilder("/bin/sh", "-c", "otter <proof.in >proof.out");
final Process p = pb.start();

等等等

当然，您还应该确保程序从正确的目录运行-幸运的是，ProcessBuilder也允许您执行此操作.

You should also ensure, of course, that the program runs from the correct directory -- fortunately, ProcessBuilder also allows you to do that.

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