Question

我试图在java中运行从cpp程序创建的可执行文件。如果我双击exe文件，它工作正常，但如果我使用ProcessBuilder运行该文件，它会因某些原因而卡住，它打印出大部分预期的输出并且不会继续，也会使整个Java程序没有响应。这是我的代码：

    String filePath = FirstScreenController.getFile().getPath();
    ProcessBuilder launcher = new ProcessBuilder("ClusteringProgram\\Release\\main.exe",filePath);
    launcher.redirectErrorStream(true);
    try {
        /*File file = FirstScreenController.getFile();
        Path newPath = Paths.get(System.getProperty("user.dir")+"\\ClusteringProgram").resolve("K12.fasta");//Moving the file to the 
        Files.copy(Paths.get(file.getPath()), newPath, StandardCopyOption.REPLACE_EXISTING);*/
        System.out.println("Execution started");
        p = launcher.start();
        InputStream stderr = p.getInputStream();
        InputStreamReader isr = new InputStreamReader(stderr);
        BufferedReader br = new BufferedReader(isr);
        String line = null;
        while ((line = br.readLine()) != null) {
            System.out.println(line);

        }
        p.waitFor();//Waiting for the process to finish running
        System.out.println("Execution completed");  
    } catch (IOException | InterruptedException  e) {e.printStackTrace();}

Answer 1

关闭你的信息流。这就是导致你挂起的原因。我写这样的代码很多。

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

    }
    br.close(); // You need this or p can hang
    p.waitFor();

~~另外，你调用launcher.redirectStandardError(true);所以你实际上需要所有这些来同时收集stdout和stderr：~~这个答案的其余部分是错误的。我不知道是什么导致了僵局。我将大型代码片段留在这里以防它是一个奇怪的库bug，并且事实证明需要使用双线程读取技术来处理它。

    final object lock = new object();
    InputStream stdout = p.getInputStream();
    InputStreamReader isr = new InputStreamReader(stdout);
    BufferedReader br = new BufferedReader(isr);
    final InputStream stderr = p.getErrorStream();
    one = new Thread() {
        public void run() {
               InputStreamReader isr2 = new InputStreamReader(stderr);
               BufferedReader br2 = new BufferedReader(isr2);
               while ((line2 = br2.readLine()) != null) {
                   synchronized(lock) {
                      System.out.println(line2);
                   }
               }
               br2.close(); // you need this or p can hang
        }  
    };
    one.start();
    while ((line = br.readLine()) != null) {
        synchronized(lock) {
            System.out.println(line);
        }
    }
    br.close(); // You need this or p can hang
    for (;;) {
        try {
            one.join();
            break;
        } catch (InterruptedException v) {
            /* if there's something that might want the main thread's attention handle it here */
        }
    }
    p.waitFor();

试图在java中运行从cpp文件创建的exe文件

1 个答案: