如何用jgit在两次提交之间归档不同的文件？

import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class JGitArchiver {
    public static void main(String[] args) throws IOException, GitAPIException {
        // 打开Git仓库
        File gitDir = new File("/path/to/repository/.git");
        try (Repository repository = Git.open(gitDir).getRepository()) {
            // 获取两次提交之间的提交对象
            ObjectId oldCommitId = repository.resolve("HEAD~1");
            ObjectId newCommitId = repository.resolve("HEAD");
            try (RevWalk revWalk = new RevWalk(repository)) {
                revWalk.markStart(revWalk.parseCommit(newCommitId));
                revWalk.markUninteresting(revWalk.parseCommit(oldCommitId));

                // 遍历提交对象
                for (RevCommit commit : revWalk) {
                    // 遍历文件树
                    RevTree tree = commit.getTree();
                    try (TreeWalk treeWalk = new TreeWalk(repository)) {
                        treeWalk.addTree(tree);
                        treeWalk.setRecursive(true);
                        while (treeWalk.next()) {
                            // 获取文件路径和模式
                            String path = treeWalk.getPathString();
                            FileMode mode = treeWalk.getFileMode(0);

                            // 归档指定文件
                            if (path.equals("path/to/archive/file.txt")) {
                                // 获取文件内容
                                ObjectId objectId = treeWalk.getObjectId(0);
                                ObjectLoader loader = repository.open(objectId);

                                // 保存文件到指定位置
                                File archiveFile = new File("/path/to/archive/file.txt");
                                try (FileOutputStream outputStream = new FileOutputStream(archiveFile)) {
                                    loader.copyTo(outputStream);
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}