java stdin 和stdout,使用重定向的stdin和stdout从Java运行外部程序

逃离我推掉我的手 2022-08-29 14:56 141阅读 0赞

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I'm trying to running an external program from a Java program and I'm having trouble. Basically what I'd like to do would be this:

Runtime.getRuntime().exec("./extprogram fileOut");

However I've found that that doesn't work - Java apparentls needs to use a Process with input and output streams and other things which I'm not experienced with.

I've looked at a number of examples across the internet (many of which are from SO), and there doesn't seem to be a simple standard way of doing this, which for someone who doesn't fully understand what's going on, can be quite frustrating.

I'm also having trouble trying to build my own code off the examples of other people's code because generally it seems most other people 1. aren't interested in redirecting stdin, and 2. aren't necessarily redirecting stdout to a file, but instead to System.out.

So, would anyone be able to point me in the direction of any good simple code templates for calling external programs and redirecting stdin and stdout? Thanks.

解决方案

If you must use Process, then something like this should work:

public static void pipeStream(InputStream input, OutputStream output)

throws IOException

byte buffer\[\] = new byte\[1024\];

int numRead = 0;

numRead = input.read(buffer);

output.write(buffer, 0, numRead);

\} while (input.available() > 0);

output.flush();

public static void main(String\[\] argv)

FileInputStream fileIn = null;