What is "the file path in tree" in the GHTreeBuilder class using the add method?

[ghost]

Hi,
I try to add a new file to my repository, I am confused about the GHTreeBuilder.add method, my code is:

public void uploadFile(File file) throws IOException {
        //...
        GHRepository repository = github.getRepository("xxx/xxx");
        GHRef main = repository.getRef("heads/"+repository.getDefaultBranch());
        GHCommit commit = repository.getCommit(main.getObject().getSha());
        GHTreeBuilder treeBuilder = repository.createTree().baseTree(commit.getTree().getSha());
        treeBuilder.add(file.getPath(), FileUtils.readFileToString(file, Charset.defaultCharset()), false);
        GHTree ghTree = treeBuilder.create();
        GHCommit newCommit = repository.createCommit().parent(commit.getSHA1()).tree(ghTree.getSha()).message("xxx").create();
        main.updateTo(newCommit.getSHA1());
    }

I read the JavaDoc with this method and got confused about "the file paths in tree".

Then I went to these pages:

• https://github-api.kohsuke.org/apidocs/org/kohsuke/github/GHBlobBuilder.html
• https://developer.github.com/v3/git/blobs/#create-a-blob

I thought the path was just the file path, and the code assumed to read it, that's it, no?

When I use the "add" method, trace the code, and find that more error messages are:

https://api.github.com/repos/saveUrl/saveUrl/git/blobs {"message":"Not Found","documentation_url":"https://docs.github.com/rest/reference/git#create-a-blob"}