How to get file by ObjectId in jgit

Question

I have some objectId from each files in my directory and some time after I want to find this file by objectId. I can make it only like hard way... but maybe there is/are some another solution/s ?

This is my way

public String findFolderDtoNameByObjectId(Repository repository, String objectId) throws IOException {
    Ref head = repository.findRef(Constants.HEAD);
    if (head == null) {
        throw new NullPointerException();
    }
    try (RevWalk walk = new RevWalk(repository)) {
        RevCommit commit = walk.parseCommit(head.getObjectId());
        RevTree tree = commit.getTree();

        try (TreeWalk treeWalk = new TreeWalk(repository)) {
            treeWalk.addTree(tree);
            treeWalk.setRecursive(true);
            while (treeWalk.next()) {
                if (treeWalk.getObjectId(0).getName().equals(objectId)) {
                    GitFileDto dto = new GitFileDto();
                    dto.setFullPath(treeWalk.getPathString());
                    dto.setName(treeWalk.getNameString());
                    dto.setObjectId(treeWalk.getObjectId(0).getName());
                    dto.setContent(getContentFromTree(treeWalk, repository));
                    return dto;         
                 } else if (treeWalk.isSubtree()) {
                    treeWalk.enterSubtree();
                }
            }
        }
    }
    return null;
}

Answer 1

My Answer is

public GitFileDto findFileDtoByObjectId(Repository repository, String objectId) throws IOException {

    Ref head = repository.findRef(HEAD);
    try (RevWalk walk = new RevWalk(repository)) {
        RevCommit commit = walk.parseCommit(head.getObjectId());
        RevTree tree = commit.getTree();

        try (TreeWalk treeWalk = new TreeWalk(repository)) {
            treeWalk.addTree(tree);
            treeWalk.setRecursive(true);
            while (treeWalk.next()) {
                ObjectId objectId1 = treeWalk.getObjectId(0);
                if (objectId1 != null && objectId.equals(objectId1.getName())) {
                    return getGitFileDto(repository, treeWalk);
                }
            }
        }
    }
    throw new Exception(String.format("There is no file with objectId: %s ", objectId));
}


private GitFileDto getGitFileDto(Repository repository, TreeWalk treeWalk) throws IOException {

    GitFileDto dto = new GitFileDto();
    dto.setFullPath(treeWalk.getPathString());
    dto.setName(treeWalk.getNameString());
    
    ObjectId objectId = treeWalk.getObjectId(0);

    dto.setObjectId(objectId.getName());

   try (ObjectReader objectReader = repository.newObjectReader()) {
        ObjectLoader objectLoader = objectReader.open(objectId);
        byte[] bytes = objectLoader.getBytes();
       
        dto.setContent(new String(bytes, StandardCharsets.UTF_8));
    }
    return dto;
}

But I don't like this, because I have to parse the whole tree by myself and I think it is wierd and slow