如何使用Java将RPM文件提取到指定目录

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-compress</artifactId>
    <version>1.26.1</version> <!-- 使用最新稳定版本 -->
</dependency>

import org.apache.commons.compress.archivers.cpio.CpioArchiveInputStream;
import org.apache.commons.compress.archivers.cpio.CpioArchiveEntry;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class RpmExtractor {

    private static final int BUFFER_SIZE = 8192;

    /**
     * 将RPM文件内容提取到指定的目标目录。
     * @param rpmFilePath RPM文件的路径。
     * @param targetDirectory 目标提取目录的路径。
     * @throws IOException 如果在执行命令或文件操作时发生错误。
     * @throws InterruptedException 如果进程被中断。
     */
    public void extractRpm(String rpmFilePath, String targetDirectory) throws IOException, InterruptedException {
        Path targetDirPath = Paths.get(targetDirectory);
        if (!Files.exists(targetDirPath)) {
            Files.createDirectories(targetDirPath);
        }

        String command = String.format("rpm2cpio %s", rpmFilePath);
        Process process = null;
        try {
            // 执行rpm2cpio命令
            process = Runtime.getRuntime().exec(command);

            // 获取rpm2cpio的标准输出流，它是一个CPIO归档流
            try (InputStream cpioRawStream = new BufferedInputStream(process.getInputStream());
                 CpioArchiveInputStream cpioStream = new CpioArchiveInputStream(cpioRawStream)) {

                CpioArchiveEntry entry;
                while ((entry = cpioStream.getNextCPIOEntry()) != null) {
                    if (entry.isDirectory()) {
                        // 创建目录
                        Path dirPath = targetDirPath.resolve(entry.getName());
                        if (!Files.exists(dirPath)) {
                            Files.createDirectories(dirPath);
                        }
                    } else if (entry.isRegularFile()) {
                        // 提取文件
                        Path filePath = targetDirPath.resolve(entry.getName());
                        // 确保父目录存在
                        Files.createDirectories(filePath.getParent());

                        try (FileOutputStream fos = new FileOutputStream(filePath.toFile())) {
                            byte[] buffer = new byte[BUFFER_SIZE];
                            int len;
                            while ((len = cpioStream.read(buffer)) != -1) {
                                fos.write(buffer, 0, len);
                            }
                        }
                        // 设置文件权限（可选，取决于需求）
                        // Files.setPosixFilePermissions(filePath, PosixFilePermissions.fromString("rwxr-xr-x"));
                    }
                    // 忽略其他类型的条目（如符号链接等），如果需要处理，可在此处添加逻辑
                }
            } finally {
                // 确保进程的错误流也被读取，防止子进程阻塞
                try (InputStream errorStream = process.getErrorStream()) {
                    // 可以选择记录错误信息
                    // String errorOutput = new String(errorStream.readAllBytes());
                    // if (!errorOutput.isEmpty()) {
                    //     System.err.println("rpm2cpio error: " + errorOutput);
                    // }
                }
            }

            // 等待进程完成并检查退出码
            int exitCode = process.waitFor();
            if (exitCode != 0) {
                // 读取错误流并抛出异常
                String errorOutput = new String(process.getErrorStream().readAllBytes());
                throw new IOException(String.format("rpm2cpio command failed with exit code %d. Error: %s", exitCode, errorOutput));
            }

        } finally {
            if (process != null) {
                process.destroy(); // 确保进程被终止
            }
        }
    }

    public static void main(String[] args) {
        String rpmFile = "/path/to/your/package.rpm"; // 替换为你的RPM文件路径
        String extractDir = "/tmp/extracted_rpm";     // 替换为目标提取目录

        RpmExtractor extractor = new RpmExtractor();
        try {
            System.out.println("开始提取RPM文件: " + rpmFile + " 到 " + extractDir);
            extractor.extractRpm(rpmFile, extractDir);
            System.out.println("RPM文件提取成功！内容已保存到: " + extractDir);
        } catch (IOException | InterruptedException e) {
            System.err.println("提取RPM文件时发生错误: " + e.getMessage());
            e.printStackTrace();
        }
    }
}