Question

我正在尝试运行命令，即：通过Java的mvn -version，但我不断收到以下错误：

public InputStream runCommand() {
        try {

            ProcessBuilder processBuilder = new ProcessBuilder("mvn -version");
            Process process = processBuilder.start();
            try {
                process.waitFor();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String s = null;
            while((s = bufferedReader.readLine())!= null){
                System.out.println(s);
            }
            System.out.println();
            return process.getInputStream();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
}

我知道此命令有效，因为我已经对其进行了手动测试。这是运行命令的代码：

AP4_Track *test_videoTrack = nullptr;
AP4_ByteStream *input = nullptr;
AP4_Result result = AP4_FileByteStream::Create(filename, AP4_FileByteStream::STREAM_MODE_READ, input);

AP4_File m_file (*input, true);

//
// Read movie tracks, and metadata, find the video track
size_t index = 0;
uint32_t m_width = 0, m_height = 0;
auto item = m_file.GetMovie()->GetTracks().FirstItem();
auto track = item->GetData();
if (track->GetType() == AP4_Track::TYPE_VIDEO) 
{
    m_width = (uint32_t)((double)test_videoTrack->GetWidth() / double(1 << 16));
    m_height = (uint32_t)((double)test_videoTrack->GetHeight() / double(1 << 16));

    std::string codec("unknown");
    auto sd = track->GetSampleDescription(0);
    AP4_String c;
    if (AP4_SUCCEEDED(sd->GetCodecString(c))) 
    {
        codec = c.GetChars();
    }

    // Find and instantiate the decoder
    AP4_Sample sample;
    AP4_DataBuffer sampleData;
    test_videoTrack->ReadSample(0, sample, sampleData);
}

有人可以指出我在做什么错吗？

Answer 1

public class LRBDemo { public static void main(String[] args) { // загрузить комплект ресурсов по умолчанию ResourceBundle rd = ResourceBundle.getBundle(SampleRB.class.getName()); System.out.println("Английская версия программы: "); System.out.println("Строка по ключу Title: " + rd.getString("title")); System.out.println("Строка по ключу StopText: " + rd.getString("StopText")); System.out.println("Строка по ключу StartText: " + rd.getString("StartText")); // загрузить комплект ресурсов для поддержки немецкого языка rd = ResourceBundle.getBundle(SampleRBde.class.getName()); System.out.println("\nНемецкая версия программы: "); System.out.println("Строка для ключа Title: " + rd.getString("title")); System.out.println("Строка по ключу StopText: " + rd.getString("StopText")); System.out.println("Строка по ключу StartText: " + rd.getString("StartText")); } }并未按照您的意图运行带有参数new ProcessBuilder("mvn -version")的{{1}}。而是尝试运行名为mvn的程序。即，程序名称本身具有两个单词，并且两个单词之间有一个空格。没有这样的程序是很有意义的！：-）

请注意，ProgramBuilder的构造函数takes a String... argument用于提供程序名称和参数。您想要的是：-version。

Java进程错误无法运行程序

1 个答案: