如何“猫” JGit中的文件？ [英] How to "cat" a file in JGit?

问题描述

前一段时间，我在Java中寻找一个嵌入式分布式版本控制系统，
，我想我已经在 JGit 中找到了，它是一个纯粹的Java实现git。
但是，示例代码或教程没有多少内容。

A while back I was looking for an embeddable distributed version control system in Java, and I think I have found it in JGit, which is a pure Java implementation of git. However, there is not much in the way of sample code or tutorials.

如何使用JGit来检索某个文件的HEAD版本例如 svn cat 或 hg cat 要做）？

How can I use JGit to retrieve the HEAD version of a certain file (just like svn cat or hg cat whould do)?

我想这涉及到一些rev-tree-walking，并且正在寻找一个代码示例。

I suppose this involves some rev-tree-walking and am looking for a code sample.

推荐答案

不幸的是，Thilo的答案不适用于最新的JGit API。这里是我找到的解决方案：

Unfortunately Thilo's answer does not work with the latest JGit API. Here is the solution I found:

File repoDir = new File("test-git");
// open the repository
Repository repository = new Repository(repoDir);
// find the HEAD
ObjectId lastCommitId = repository.resolve(Constants.HEAD);
// now we have to get the commit
RevWalk revWalk = new RevWalk(repository);
RevCommit commit = revWalk.parseCommit(lastCommitId);
// and using commit's tree find the path
RevTree tree = commit.getTree();
TreeWalk treeWalk = new TreeWalk(repository);
treeWalk.addTree(tree);
treeWalk.setRecursive(true);
treeWalk.setFilter(PathFilter.create(path));
if (!treeWalk.next()) {
  return null;
}
ObjectId objectId = treeWalk.getObjectId(0);
ObjectLoader loader = repository.open(objectId);

// and then one can use either
InputStream in = loader.openStream()
// or
loader.copyTo(out)

我希望它更简单。

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