使用Runtime.exec在Linux中使用echo创建文件? [英] Create a file using Runtime.exec using echo in linux?
问题描述
我在Java中使用Runtime.exec时遇到问题,似乎有些命令可以工作,而其他命令则不能。例如,如果我运行
I'm having trouble using Runtime.exec in Java, it seems some commands work while others do not. For example if I run
echo some data > data.txt
在我的终端中,它可以正常工作,但是如果我尝试使用Java来做到这一点
In my terminal it works fine, however if I try and use Java to do this it doesn't work.
Runtime mRuntime = Runtime.getRuntime();
Process mProcess = mRuntime.exec("echo some data > data.txt");
mProcess.waitFor();
有什么理由吗?
推荐答案
echo
并不是真正的命令,因为它具有可以运行的二进制文件。它是shell的内置函数。
echo
is not a real command in the sense that it has a binary that you can run. It is a built-in function of shells.
您可以尝试在Windows中运行像 cmd.exe
这样的shell。或 sh
在Linux / Mac / Unix中,然后传递命令以字符串形式运行。就像使用'bash'一样,您可以这样做:
You could try running a shell like cmd.exe
in Windows or sh
in Linux/Mac/Unix, and then passing the command to run as a string.. Like using 'bash', you can do this:
编辑,因为使用运行时
edit because redirection is a little different using Runtime
要正确进行重定向,您应该使用 exec
的形式,该格式采用 String []
。
To do redirection correctly, you should be using the form of exec
that takes a String[]
.
这是一个适用于重定向的简单示例。
Here's a quick example that does work with redirection.
public class RunTest {
public static void main(String[] args) throws Exception {
String [] commands = { "bash", "-c", "echo hello > hello.txt" };
Runtime.getRuntime().exec(commands);
}
}
但是如果您只想创建文件,则可以可以使用Java自己的API创建文件,而不是使用 Runtime
。
But if you just wanted to create a file, you could create the file with Java's own API rather than use Runtime
.
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