java - ProcessBuilder 不输出任何内容

Question

我使用 Process Builder 运行 shell 命令:

try {
    ProcessBuilder lmBuilder = new ProcessBuilder("/home/istanbul/srilm/bin/i686-m64/ngram-count", "-text", modelPath, "-order", "3", "-lm", modelOutputPath);
    lmBuilder.redirectErrorStream();
    final Process lmProcess = lmBuilder.start();
    int result = lmProcess.waitFor(); //result becomes 0
    InputStream is = lmProcess.getInputStream();
    InputStreamReader isr = new InputStreamReader(is);
    BufferedReader br = new BufferedReader(isr);

    String line;
    while ((line = br.readLine()) != null) {
        System.out.println(line);
    }

} catch (IOException | InterruptedException e) {
    e.printStackTrace();
}

当我检查命令的输出时，我发现它工作正常。当我通过 shell 运行它时，我看到输出:

warning: discount coeff 1 is out of range: 0
warning: discount coeff 7 is out of range: 1.06876
warning: discount coeff 7 is out of range: 2.09945

但是，当我通过流程构建器运行它时，我看不到任何输出。

有什么想法吗？

Answer 1

lmBuilder.redirectErrorStream();

这是不正确的。

此方法仅告诉您是否将 stderr 重定向到 stdout；它并不指示 stderr 应重定向到它。

你应该使用的是:

lmBuilder.redirectErrorStream(true);