如何在 Java 中捕获 shell 命令的退出状态？
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How to capture the exit status of a shell command in Java?
提问by Niranjan Subramanian
I'm creating a Junit test file for my CSVreader. I'm reading the contents of CSV files and writing the contents into another file. I want to compare them using diff utility and I want to use the exit status of diff to know whether the contents are same or not. Generally $? gives the exit status but I don't know how to capture it and use it in my code. Can anyone help me in this regard?
我正在为我的 CSVreader 创建一个 Junit 测试文件。我正在读取 CSV 文件的内容并将内容写入另一个文件。我想使用 diff 实用程序比较它们，我想使用 diff 的退出状态来知道内容是否相同。一般$? 给出退出状态，但我不知道如何捕获它并在我的代码中使用它。任何人都可以在这方面帮助我吗？
This is how my code looks
这是我的代码的样子
boolean hasSameContents = false;
command="diff "+mp.get("directory")+"/"+fileName+" "+mp.get("outdir")+"/"+fileName;
p= Runtime.getRuntime().exec(command);
p.waitFor();
After this I want to get the exit status and use it in a if condition like this
在此之后，我想获得退出状态并在这样的 if 条件下使用它
if(exit_status==0)
hasSameContents = true;
else
hasSameContents = false;
Even alternative suggestions appreciated. :)
甚至替代建议表示赞赏。:)
回答by MadProgrammer
You're looking for Process#exitValue
您正在寻找Process#exitValue
String command = "diff "+mp.get("directory")+"/"+fileName+" "+mp.get("outdir")+"/"+fileName;
Process p = Runtime.getRuntime().exec(command);
p.waitFor();
int exitStatus = p.exitValue();
Don't forget, you should read the contents of the InputStreameven if you don't care, some processes will choke (not finish) until the output buffer has been read...
不要忘记，InputStream即使您不在乎，也应该阅读内容，某些进程会阻塞（未完成），直到读取了输出缓冲区...
回答by Aditya Jain
You can try using ProcessBuilderclass to create a Processobject, whose exitValue()should help you.
您可以尝试使用ProcessBuilder类来创建一个Process对象，它exitValue()应该可以帮助您。
回答by Daniel Pryden
回答by logoff
Use method waitFor() of class Process. It returns an int, the return value of the process.
使用类 Process 的方法waitFor()。它返回一个 int，即进程的返回值。
