ProcessBuilder 和 Runtime.exec() 的区别 [英] Difference between ProcessBuilder and Runtime.exec()

问题描述

我正在尝试从 java 代码执行外部命令，但我注意到 Runtime.getRuntime().exec(...) 和 new ProcessBuilder 之间存在差异(...).start().

I'm trying to execute an external command from java code, but there's a difference I've noticed between Runtime.getRuntime().exec(...) and new ProcessBuilder(...).start().

使用 Runtime 时:

Process p = Runtime.getRuntime().exec(installation_path + 
                                       uninstall_path + 
                                       uninstall_command + 
                                       uninstall_arguments);
p.waitFor();

exitValue 为 0，命令正常终止.

the exitValue is 0 and the command is terminated ok.

但是，使用 ProcessBuilder:

Process p = (new ProcessBuilder(installation_path +    
                                 uninstall_path +
                                 uninstall_command,
                                 uninstall_arguments)).start();
p.waitFor();

退出值为 1001，命令在中间终止，尽管 waitFor 返回.

the exit value is 1001 and the command terminates in the middle, although waitFor returns.

我应该怎么做才能解决 ProcessBuilder 的问题?

What should I do to fix the problem with ProcessBuilder?

推荐答案

Runtime.getRuntime().exec(...) 的各种重载采用字符串数组或单个字符串.exec() 的单字符串重载会将字符串标记为参数数组，然后将字符串数组传递给一个接受字符串的 exec() 重载大批.另一方面，ProcessBuilder 构造函数只接受一个可变的字符串数组或一个 List 字符串，其中数组或列表中的每个字符串都被假定为一个单独的争论.无论哪种方式，获得的参数都会被组合成一个字符串，然后传递给操作系统以执行.

The various overloads of Runtime.getRuntime().exec(...) take either an array of strings or a single string. The single-string overloads of exec() will tokenise the string into an array of arguments, before passing the string array onto one of the exec() overloads that takes a string array. The ProcessBuilder constructors, on the other hand, only take a varargs array of strings or a List of strings, where each string in the array or list is assumed to be an individual argument. Either way, the arguments obtained are then joined up into a string that is passed to the OS to execute.

例如，在 Windows 上，

So, for example, on Windows,

Runtime.getRuntime().exec("C:DoStuff.exe -arg1 -arg2");

将运行带有两个给定参数的 DoStuff.exe 程序.在这种情况下，命令行被标记并重新组合在一起.然而，

will run a DoStuff.exe program with the two given arguments. In this case, the command-line gets tokenised and put back together. However,

ProcessBuilder b = new ProcessBuilder("C:DoStuff.exe -arg1 -arg2");

将失败，除非 C: 中有一个名为 DoStuff.exe -arg1 -arg2 的程序.这是因为没有标记化:假设要运行的命令已经被标记化.相反，您应该使用

will fail, unless there happens to be a program whose name is DoStuff.exe -arg1 -arg2 in C:. This is because there's no tokenisation: the command to run is assumed to have already been tokenised. Instead, you should use

ProcessBuilder b = new ProcessBuilder("C:DoStuff.exe", "-arg1", "-arg2");

或者替代

List<String> params = java.util.Arrays.asList("C:DoStuff.exe", "-arg1", "-arg2");
ProcessBuilder b = new ProcessBuilder(params);

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