java进程

k4emjkb1  于 2021-06-30  发布在  Java
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我正在学习一门操作系统课程,教授向我们展示了一些java进程管理的例子。这些例子是在linux操作系统上显示的,我正在尝试修改一些在windows中产生错误的代码。
下面的代码创建了一个进程,该进程列出目录中的文件,并且只用于理解父级和子级交互的一些机制。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.stream.Collectors;

public class SimpleProcess1 {
    public static void main(String[] args) throws InterruptedException, IOException {

        ProcessBuilder pb = new ProcessBuilder("ls", "-la");
        System.out.println("Run command");
        Process process = pb.start(); 

        while (process.isAlive()) {
            System.out.println("The process is still runnning");
        }

        System.out.println("The process stopped. Any errors? " + (process.exitValue() == 0 ? "No" : "Yes"));

        String text = new BufferedReader( new InputStreamReader(process.getInputStream(), StandardCharsets.UTF_8)).lines().collect(Collectors.joining("\n"));

        System.out.println("Echo Output:\n" + text);
    }
}

我试图修改创建“ls”进程的代码行(在windows中不存在)

ProcessBuilder pb = new ProcessBuilder("dir");

但我在运行时遇到以下错误:

C:\java\Processi>java SimpleProcess1
Run command
Exception in thread "main" java.io.IOException: Cannot run program "dir": CreateProcess error=2, The system cannot find the file specified
        at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1128)
        at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1071)
        at SimpleProcess1.main(SimpleProcess1.java:13)
Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified
        at java.base/java.lang.ProcessImpl.create(Native Method)
        at java.base/java.lang.ProcessImpl.<init>(ProcessImpl.java:478)
        at java.base/java.lang.ProcessImpl.start(ProcessImpl.java:154)
        at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1107)
        ... 2 more

我应该如何修改命令?

暂无答案!

目前还没有任何答案,快来回答吧!

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