如何从Java提取RPM文件到特定的package

Question

I want to extract a rpm file to target directory from Java code. I'm aware of the following approaches:

• Run rpm2cpio mypackage.rpm | (cd /target/dir; cpio -idmv) rpm2cpio mypackage.rpm | (cd /target/dir; cpio -idmv) as command line. This is not really Java and I worry the portability by hardcoding this command.
• Use CpioArchiveInputStream . I hit java.io.IOException: Unknown magic when trying to read the rpm file. My guess is that this library is too old to adapt to new archive/compression types.

Is there a better approach that I'm not aware of? Ideally something that works like a TarArchiveInputStream would be perfect.

Answer 1

This is the middle ground that I found working:

Runtime rt = Runtime.getRuntime();
Process proc = rt.exec(String.format("rpm2cpio %s", packagePath));
try (CpioArchiveInputStream cpioStream = new CpioArchiveInputStream(proc.getInputStream())) {
    System.out.println(cpioStream.getNextCPIOEntry().getName());
}

Not perfect, but makes it easier so that we only rely on a new process to read file.