执行 Linux 命令的方法失败

Question

我创建了以下方法来执行 Linux 命令：

public void executeGetLogs(){
    try{
        Runtime rt = Runtime.getRuntime();
        String [] commands = {helper.getPythonPath(), helper.getLogsMainScript(), helper.getLogsManagementUrl(), helper.getLogsManagementUrlPrefix(), helper.getLogsManagementUsername(), helper.getLogsManagementPassword(), helper.getLogsNet(), helper.getLogsStorageUrl(), helper.getLogStorageUsername(), helper.getLogStoragePassword()};
        Process proc = rt.exec(commands);

        BufferedReader stdInput = new BufferedReader(new 
                InputStreamReader(proc.getInputStream()));

        BufferedReader stdError = new BufferedReader(new 
                InputStreamReader(proc.getErrorStream()));

        // read the output from the command
        logger.debug("Standard output from execution of get_logs:\n");
        String s = null;
        while ((s = stdInput.readLine()) != null) {
            logger.debug(s);
        }

        // read any errors from the attempted command
        logger.debug("Standard error from execution of get_logs (if any):\n");
        while ((s = stdError.readLine()) != null) {
            logger.debug(s);
        }
    }
    catch(IOException e){
        logger.debug("Execution exception: " + e);
    }
}

该方法似乎开始正常工作，但随后失败。

调试显示以下输出：

2017-04-21 12:27:42,391 DEBUG  Standard output from execution of get_logs:

2017-04-21 12:27:44,360 DEBUG  411 new files found
2017-04-21 12:27:44,363 DEBUG  Downloading files...
2017-04-21 12:27:44,446 DEBUG  Standard error from execution of get_logs (if any):

我希望看到的是

2017-04-21 12:27:44,360 DEBUG  411 new files found
2017-04-21 12:27:44,363 DEBUG  Downloading files...
Downloaded 10 of 447
Downloaded 20 of 447
Downloaded 30 of 447

依此类推，直到下载了 447 个，共 447 个。

我也看到没有下载任何东西。

我的命令运行当我在终端中运行它时。

是否有可能 Java 中的某些内容导致它退出？一件事是处理每个 10 块可能需要几秒钟。是否有可能

while ((s = stdInput.readLine()) != null) {
    logger.debug(s);
}

只是看到一个空值，因为 stdInput 还没有出现，所以它退出了循环？如果是这样，我该如何解决？

Answer 1

在 java 中执行代码的更好方法是 ProcessBuilder。示例：

//Create the command.
ProcessBuilder command = new ProcessBuilder(helper.getPythonPath(), helper.getLogsMainScript(), helper.getLogsManagementUrl(), helper.getLogsManagementUrlPrefix(), helper.getLogsManagementUsername(), helper.getLogsManagementPassword(), helper.getLogsNet(), helper.getLogsStorageUrl(), helper.getLogStorageUsername(), helper.getLogStoragePassword());
//Will show console output in java console.
command .inheritIO();
//Launches de command.
Process process= command .start();

希望对您有所帮助。

Answer 2

追根究底。我需要等待进程结束。这可以通过以下代码完成：

proc.waitFor();

我的方法现在看起来像这样：

public void executeGetLogs(){
    try{
        Runtime rt = Runtime.getRuntime();
        String [] commands = {helper.getPythonPath(), helper.getLogsMainScript(), helper.getLogsManagementUrl(), helper.getLogsManagementUrlPrefix(), helper.getLogsManagementUsername(), helper.getLogsManagementPassword(), helper.getLogsNet(), helper.getLogsStorageUrl(), helper.getLogStorageUsername(), helper.getLogStoragePassword()};
        Process proc = rt.exec(commands);

        BufferedReader stdInput = new BufferedReader(new 
            InputStreamReader(proc.getInputStream()));

        try{
            proc.waitFor();
        }
        catch(InterruptedException e){
            logger.debug("Interrupted Exception : " + e);
        }

        BufferedReader stdError = new BufferedReader(new 
            InputStreamReader(proc.getErrorStream()));

        // read the output from the command
        logger.debug("Standard output from execution of get_logs:\n");
        String s = null;
        while ((s = stdInput.readLine()) != null) {
            logger.debug(s);
        }

        // read any errors from the attempted command
        logger.debug("Standard error from execution of get_logs (if any):\n");
        while ((s = stdError.readLine()) != null) {
            logger.debug(s);
        }
    }
    catch(IOException e){
        logger.debug("Execution exception: " + e);
    }
}

执行 Linux 命令的方法失败

Method to execute Linux command fails

java

linux

command