不阻塞地获取进程输出

我想获得一个进程的输出（Git.exe准确地说）并将其转换为 String 对象。以前有时我的代码被阻止。然后我发现这是因为这个过程'ErrorStream有一些输出，我必须手动捕获它（我对此不感兴趣）。我将我的代码更改为：

public static String runProcess(String executable, String parameter) {
    try {
        String path = String.format("%s %s", executable, parameter);
        Process pr = Runtime.getRuntime().exec(path);

        // ignore errors
        StringWriter errors = new StringWriter();
        IOUtils.copy(pr.getErrorStream(), errors);

        StringWriter writer = new StringWriter();
        IOUtils.copy(pr.getInputStream(), writer);

        pr.waitFor();
        return writer.toString();
    } catch (Exception e) {
        return null;
    }
}

现在它大部分工作正常，但话又说回来，有时它会在这一行再次被阻止：IOUtils.copy(pr.getErrorStream(), errors);.

有什么方法可以让我得到输出git.exe不撞块？谢谢。

使用这个漂亮的文章和StreamGobbler那里描述的类（我修改了一点）我解决了问题。我的实施StreamGobbler:

class StreamGobbler extends Thread {
    InputStream is;
    String output;

    StreamGobbler(InputStream is) {
        this.is = is;
    }

    public String getOutput() {
        return output;
    }

    public void run() {
        try {
            StringWriter writer = new StringWriter();
            IOUtils.copy(is, writer);
            output = writer.toString();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }
}

我的功能是：

public static String runProcess(String executable, String parameter) {
    try {
        String path = String.format("%s %s", executable, parameter);
        Process pr = Runtime.getRuntime().exec(path);

        StreamGobbler errorGobbler = new StreamGobbler(pr.getErrorStream());
        StreamGobbler outputGobbler = new StreamGobbler(pr.getInputStream());

        // kick them off concurrently
        errorGobbler.start();
        outputGobbler.start();

        pr.waitFor();
        return outputGobbler.getOutput();
    } catch (Exception e) {
        return null;
    }
}