首先将字符串转换为 ObjectId 然后让 RevWalk 查看它可能更容易

It is probably easier to first convert the string into an ObjectId and then have the RevWalk look it up.

ObjectId commitId = ObjectId.fromString("ab434...");
try (RevWalk revWalk = new RevWalk(repository)) {
  RevCommit commit = revWalk.parseCommit(commitId);
}