Question

鉴于代码：

extend DBTestCase

当我运行代码时，它将执行public String execCommand(String command, File folder) { if (folder.isDirectory() && Files.isDirectory(folder.toPath())) { logger.info("It is a directory!"); //yes, is a directory! } try { Process runtimeProc = Runtime.getRuntime().exec(command, null, folder); Process builderProc = new ProcessBuilder(command) .directory(folder) .redirectErrorStream(true) .start(); } catch (InterruptedException | IOException e) { logger.log(Level.SEVERE, e, e::getMessage); throw new IllegalStateException(e); } }而没有问题，但runtimeProc将抛出IOException：

无法运行程序＆＃34; myexecutable＆＃34; （在目录中＆＃34; / home / testing / 1acbcd01-76d2-4981-8fd3-b863d6f9ede8＆＃34;）：错误= 20，不是 directory：java.io.IOException：无法运行程序＆＃34; myexecutable action＆＃34; （在目录＆＃34; / home / testing / 1acbcd01-76d2-4981-8fd3-b863d6f9ede8＆＃34;）：错误= 20，不是目录

阅读完代码后，我注意到内部builderProc使用了Runtime.exec()类。如果一方正在工作而另一方正在抛出异常，这怎么可能？更重要的是：如何修复它？

调试＆＃34;爆炸点＆＃34;在jdk＆＃39; s ProcessBuilder类内部：

ProcessBuilder

Full StackTrace：

try {
            return ProcessImpl.start(cmdarray,
                                     environment,
                                     dir,
                                     redirects,
                                     redirectErrorStream);
        } catch (IOException | IllegalArgumentException e) {
            String exceptionInfo = ": " + e.getMessage();
            Throwable cause = e;
            if ((e instanceof IOException) && security != null) {
                // Can not disclose the fail reason for read-protected files.
                try {
                    security.checkRead(prog);
                } catch (SecurityException se) {
                    exceptionInfo = "";
                    cause = se;
                }
            }
            // It's much easier for us to create a high-quality error
            // message than the low-level C code which found the problem.
            throw new IOException(
                "Cannot run program \"" + prog + "\""
                + (dir == null ? "" : " (in directory \"" + dir + "\")")
                + exceptionInfo,
                cause);
        }

Answer 1

我发现了不同之处：

默认情况下Runtime.getRuntime().exec会对输入进行标记，在ProcessBuilder的情况下，它将按原样执行命令（即：不会标记化）

这就是Runtime版本可以正常工作的原因，它会将命令分离为： ["buildr", "run"]另一方面ProcessBuilder将运行为：["buildr run"]。

解决方案：在使用ProcessBuilder之前进行标记，例如：

String[] cmdAsTokens = command.split(" ");
Process process = new ProcessBuilder(cmdAsTokens)
                .directory(folder)
                .redirectErrorStream(true)
                .start();

ProcessBuilder与Runtime.getRuntime（）。exec的行为不同

1 个答案: