与另一个进程Java交互 [英] Interacting with another process Java

问题描述

我正在尝试与Java中的另一个进程进行交互。它是这样的......

I am trying to interact with another process in Java. It goes like this...

Runtime rt;
Process pr=rt.exec("cmd");

然后我使用...发送一些命令到进程...

then I send some commands to the process using...

BufferedReader processOutput = new BufferedReader(new InputStreamReader(pr.getInputStream()));
BufferedWriter processInput = new BufferedWriter(new OutputStreamWriter(pr.getOutputStream()));

processInput.write("gdb");
processInput.flush();

我现在不关心输出..所以我试着用它来忽略它

I don't care about the output for now.. so I try to ignore it using..

while(processOutput.readLine() != null);

但这个循环永远挂起。我知道这是因为进程仍在运行并且不发送空值。我现在不想终止它。我必须根据用户输入发送命令然后获得输出..

but this loops hangs forever. I know this is because process is still running and doesn't sends a null. I don't want to terminate it now. I have to send commands based on user Input and then get the output..

如何做到这一点？换句话说，我想在执行某些命令后刷新Process输出流或忽略它，并在我想要的时候读取它。

How to do this? In other words I want to flush the Process output stream or ignore it after executing some commands and read it only when I want to.

推荐答案

使用单独的线程读取输出。这样，只要有输出就会被读取，但不会阻止你。

Use a separate thread to read the output. This way, as long as there is output it will be read, but will not block you.

例如，创建这样一个类：

For example, create such a class:

public class ReaderThread extends Thread {

    private BufferedReader reader = null;
    public ReaderThread(BufferedReader reader) {
        this.reader = reader;
    }

    @Override
    public void run() {
        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
        }
        catch(IOException exception) {
            System.out.println("!!Error: " + exception.getMessage());
        }
    }
}

在您的主要课程中，代替 while（processOutput.readLine（）！= null）; ，请致电：

And in your main class, instead of while(processOutput.readLine() != null);, call:

ReaderThread reader = new ReaderThread(processOutput);
reader.start();

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