从Java中高效提取RPM文件内容到指定目录

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-compress</artifactId>
    <version>1.21</version> <!-- 请使用最新稳定版本 -->
</dependency>

implementation 'org.apache.commons:commons-compress:1.21' // 请使用最新稳定版本

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

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;

public class RpmExtractor {

    private static final int BUFFER_SIZE = 4096;

    /**
     * 从RPM文件中提取所有内容到指定目标目录。
     *
     * @param rpmFilePath RPM文件的路径
     * @param targetDirectoryPath 目标目录的路径
     * @throws IOException 如果在文件操作或命令执行过程中发生错误
     */
    public void extractRpm(String rpmFilePath, String targetDirectoryPath) throws IOException {
        Path targetDir = Paths.get(targetDirectoryPath);
        if (!Files.exists(targetDir)) {
            Files.createDirectories(targetDir);
        }

        Process process = null;
        try {
            // 构建 rpm2cpio 命令
            String command = String.format("rpm2cpio %s", rpmFilePath);
            System.out.println("Executing command: " + command);

            // 执行命令并获取其标准输出流
            process = Runtime.getRuntime().exec(command);

            // 检查进程是否成功启动
            if (process == null) {
                throw new IOException("Failed to start rpm2cpio process.");
            }

            // 使用CpioArchiveInputStream读取rpm2cpio的输出
            try (InputStream cpioOutput = process.getInputStream();
                 CpioArchiveInputStream cpioStream = new CpioArchiveInputStream(cpioOutput)) {

                CpioArchiveEntry entry;
                while ((entry = cpioStream.getNextEntry()) != null) {
                    if (!cpioStream.canReadEntryData(entry)) {
                        System.err.println("Cannot read entry data for: " + entry.getName());
                        continue;
                    }

                    Path entryPath = targetDir.resolve(entry.getName()).normalize(); // 防止路径遍历攻击
                    // 确保提取路径在目标目录内
                    if (!entryPath.startsWith(targetDir)) {
                        System.err.println("Attempted path traversal detected: " + entry.getName());
                        continue;
                    }

                    if (entry.isDirectory()) {
                        Files.createDirectories(entryPath);
                    } else {
                        Path parentDir = entryPath.getParent();
                        if (parentDir != null && !Files.exists(parentDir)) {
                            Files.createDirectories(parentDir);
                        }
                        try (OutputStream fos = Files.newOutputStream(entryPath, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING)) {
                            byte[] buffer = new byte[BUFFER_SIZE];
                            int bytesRead;
                            while ((bytesRead = cpioStream.read(buffer)) != -1) {
                                fos.write(buffer, 0, bytesRead);
                            }
                        }
                        // 设置文件权限 (可选，CPIO entry 包含权限信息，但Java NIO默认不直接应用)
                        // 可以通过 Files.setPosixFilePermissions(entryPath, PosixFilePermissions.fromString("rwxr-xr-x")); 等方式设置
                        // 但这需要更复杂的权限解析逻辑，这里仅做提示
                    }
                    System.out.println("Extracted: " + entry.getName());
                }
            } finally {
                // 等待进程结束并获取退出码
                int exitCode = -1;
                try {
                    exitCode = process.waitFor();
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt(); // 重新设置中断状态
                    System.err.println("Process interrupted: " + e.getMessage());
                }
                if (exitCode != 0) {
                    // 读取错误流，以便诊断问题
                    try (InputStream errorStream = process.getErrorStream()) {
                        String errorMessage = new String(errorStream.readAllBytes());
                        System.err.println("rpm2cpio exited with error code " + exitCode + ": " + errorMessage);
                    }
                    throw new IOException("rpm2cpio command failed with exit code: " + exitCode);
                }
            }

        } catch (IOException e) {
            System.err.println("Error extracting RPM: " + e.getMessage());
            throw e;
        } finally {
            if (process != null) {
                process.destroy(); // 确保进程被终止
            }
        }
    }

    public static void main(String[] args) {
        // 示例用法：请替换为实际的RPM文件路径和目标目录
        String rpmFile = "/path/to/your/package.rpm";
        String targetDir = "/path/to/extract/to";

        // 确保替换为实际存在的RPM文件路径和可写的目录
        // 例如：
        // String rpmFile = "/home/user/test.rpm";
        // String targetDir = "/tmp/extracted_rpm";

        RpmExtractor extractor = new RpmExtractor();
        try {
            extractor.extractRpm(rpmFile, targetDir);
            System.out.println("RPM extracted successfully to: " + targetDir);
        } catch (IOException e) {
            System.err.println("Failed to extract RPM: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

String rpmFile = "/home/user/my-package-1.0-1.x86_64.rpm";
String targetDir = "/tmp/extracted_rpm";