平台独立的方式来启动程序的路径？

Question

在Java中是否有一种platform-independent方式来启动一个外部进程来执行它使用系统路径找到的程序

它至少应该在Windows、Linux和Mac上工作。

通常，您必须给出可执行文件的完整路径，如下所示：

new ProcessBuilder("/some/path/execfile", "arg").start();

可以通过启动shell来启动系统路径上的程序：

new ProcessBuilder("/bin/bash", "-c", "execfile", "arg").start();

但这在OS:s之间是不可移植的(这是提供给this question的解决方案)。

Answer 1

ProcessBuilder确实使用了$PATH。

import java.io.*;

public class ProcessBuilderTest {
    public static void main(String... args) throws Exception {
        ProcessBuilder pb = new ProcessBuilder(args);
        pb.redirectErrorStream(true);
        Process p = pb.start();
        int exitCode = p.waitFor();
        printStream(p.getInputStream());
        printStream(p.getErrorStream());
        System.out.println("Exit code: " + exitCode);
    }

    static void printStream(InputStream stream) throws IOException {
        try (BufferedReader br = new BufferedReader(new InputStreamReader(stream))) {
            String line;
            while ((line = br.readLine()) != null) {
                System.out.println(line);
            }
        }
    }
}

在MacOS上运行此命令：

robert@mac:~$ java ProcessBuilderTest.java ls *.java
ProcessBuilderTest.java
Exit code: 0
robert@mac:~$ java ProcessBuilderTest.java ls *.class
ls: cannot access '*.class': No such file or directory
Exit code: 2
robert@mac:~$ java ProcessBuilderTest.java which ls
/usr/local/opt/coreutils/libexec/gnubin/ls
Exit code: 0
robert@mac:~$

在Linux上也是如此：

robert@linux:~$ java ProcessBuilderTest.java ls *.java
ProcessBuilderTest.java
Exit code: 0
robert@linux:~$ java ProcessBuilderTest.java ls  *.class
ls: cannot access '*.class': No such file or directory
Exit code: 2
robert@linux:~$ java ProcessBuilderTest.java which ls
/usr/bin/ls
Exit code: 0
robert@linux:~$

我不使用Windows，所以不能对其进行测试。